So, You Want to Make Steak Crostini for the Holidays?
Alright, let me level with you—every December, it's like clockwork. My family asks, So, are you doing your steak crostini thing again? And every year, I pretend it's a real debate. Truth? I kind of love the fuss (though my shoulders ache after caramelizing onions for an hour, but whatever, it’s the holidays). The first time I made these little guys, I accidentally used an entire jar of horseradish and let’s just say, my mother-in-law found out she can cry at holiday parties. Oops. Live and learn! This dish has been a staple ever since—minus the blubbering. Try not to panic if you’re eyeballing the steak and thinking, "Is this enough for everyone?" It’s just an appetizer! But, as my Uncle Dave says, "Nobody ever got mad at a double batch."
Why I Always End Up Serving These
I make this when I want to look like I have my act together—honestly, friends think I'm fancy (don't tell them I sometimes use leftover roast beef instead of searing a steak!). My family goes bananas for the combo of crispy bread, creamy horseradish sauce, and the sweet, jammy onions. Oh, and if I’m feeling lazy, I forgo the homemade crostini in favor of a decent store-bought baguette. Don’t judge; holiday chaos is real. Even the skeptical cousin who doesn’t “do” red meat comes back for seconds—unless I mess up and underseason the steak, which I did last year. Won’t make that mistake again.
Here’s What Goes In These Crostini (And Some Cheeky Swaps)
- 1 baguette (or, in a pinch, those pre-sliced toasts from Trader Joe’s—SO easy if you’re short on time!)
- 300g (about 10oz) steak – I love ribeye, but honestly, sirloin or even leftover roast works if you’re tight on budget.
- 2 large onions, thinly sliced—Yellow is my go-to, but my grandmother swears red onions make it sweeter (not convinced, but go for it if you like!)
- 2 tablespoons olive oil—Don’t sweat it if you use butter; sometimes I even do half-and-half for extra flavor.
- For the sauce: Half a cup of sour cream (Greek yogurt also works), 2 tablespoons horseradish (prepared OR fresh-grated; I’ve even used wasabi once, not my best moment), 1 teaspoon Dijon, a squeeze of lemon, and salt and pepper.
- Fresh chives for garnish, but parsley, scallions, or nada if you’re out
- Salt and pepper, to taste
How I Put These Together (And Occasionally Get Distracted)
- Toast the baguette slices: Heat your oven to about 190°C (375°F, or thereabouts). Slice the baguette into roughly 1cm (half-inch) slices. Lay them on a baking tray, drizzle with olive oil and a pinch of salt. Bake for, mmm, 6–8 minutes, flipping once, until golden. Sometimes I forget to flip them and only one side is crunchy—still good, honestly.
- Caramelize those onions: This is where patience pays off. Add oil to a skillet, medium-low heat, throw in the onions with a pinch of salt. Stir now and then (and don’t wander off watching old Bake Off clips like I sometimes do), for about 30–40 minutes, until they’re golden and super soft. Splash a bit of balsamic in near the end if you want extra depth. If it looks a bit weird halfway through—trust the process.
- Prepare the steak: Take the steak out to warm up while you finish onions. Season generously (don’t be shy here!). Get a pan searing hot—I mean hot. Sear steak a couple minutes per side for medium-rare, or longer if you must. Rest for at least 5 minutes before you slice it as thin as your patience allows. This is when I usually sneak a bit for "quality control."
- Mix up the sauce: Stir together sour cream, horseradish, Dijon, lemon, salt, and pepper. Taste and, if you’re like me, immediately add more horseradish. Or less, if you still remember that tearjerker year.
- Assemble: Spread a generous smear of horseradish sauce on each crostini, top with a few caramelized onions, then fan out the steak slices on top. Finish with chives—and, if you’re feeling festive, a tiny crack of black pepper.
Notes That Only Experience Teaches (Trust Me)
- Don’t skimp on the onion time. I once tried to speed it up with higher heat—ended up with onion jam and an angry smoke alarm.
- Actually, letting the steak rest longer makes slicing easier. I get impatient and regret it every time.
- If your bread is a bit stale, it works even better—less floppy crostini!
Variations I’ve (Sometimes Regrettably) Tried
- Swap steak for roast beef—super quick, just don’t tell my foodie friends or they’ll roll their eyes.
- Adding blue cheese crumbles is…divisive. My sister loves it; my nephew said it was “too funky.”
- I once tried a vegan version with roasted mushrooms and cashew cream—eh, it was fine, but it’s not a steak crostini. Lesson learned.
What You Might Need (But Don’t Panic If You Don’t Have Everything)
- Baking sheet—though honestly, I’ve used a pizza tray in a pinch.
- Heavy-bottomed skillet for steak and onions. If yours isn’t nonstick, just use a bit extra oil, it’ll be fine.
- Sharp knife—though if yours is dull, saw gently or ask a pal to bring one.
If you're missing a pan, use the grill or broiler—just keep an eye on things. Distractions happen (speaking from experience here).
How Long Do They Last? (Not Long in My House)
Technically these will stay tasty in the fridge for a day or two, but realistically, they disappear before the night is over. Leftovers? What leftovers. (On the rare occasion I hide a few, I think they taste better the next day—just pop back in the oven to crisp up again.)
Serving These Up Like a Pro (Or Just Like Me)
I pile them on a big old board, sprinkle a bit extra chive, and set out napkins because these are messy. Sometimes we pair them with prosecco, other times just strong black tea if we're feeling particularly English. On Christmas Eve, I sneak a few onto the Santa plate—can’t hurt, right?
Pro Tips I Wish I Knew Earlier
- Letting the bread cool down before topping keeps things crisp. I used to rush this and ended up with soggy bites. Bleh.
- Don’t overdo the horseradish until you taste. Trust me, fiery is not always festive.
- Slice steak after it rests, not before. I know I keep saying it, but I’ve made this mistake more than twice.
People Ask Me… (And Sometimes I Have to Google It Too!)
- Can I make these ahead? Definitely! Assemble just before serving, but you can do sauce, steak (sliced), and onions the day before. Bread gets stale if topped too early.
- What’s the best steak cut? I’ll say ribeye for flavor, but sirloin or even good ol’ flank will do. Once I used fillet, but it was a bit boring. Just don’t use stew meat.
- How spicy is the horseradish sauce? Up to you! Start mild; some jars are *way* stronger than others. It’s a little unpredictable, like the British weather.
- Any sources for more tips? Totally. Check out this Serious Eats onion guide for perfect caramelization, or Smitten Kitchen’s party snacks for more appetizer inspo.
- How long do caramelized onions keep? Honestly, I think they improve over three days in the fridge—but who has that kind of willpower?
By the way, do you ever start a holiday project and halfway through remember that you forgot to take the butter out to soften, so the cookies get bumped an hour and suddenly it's midnight and you're still cleaning up onion peels? No? Just me? Well, anyway. Even if you’re frazzled, these crostini make it look like you’ve got everything under control—just don’t tell anyone how easy they secretly are. Happy holidays and happy nibbling!
Ingredients
- 1 French baguette, sliced into ½-inch rounds
- ¼ cup olive oil
- 1 lb beef sirloin steak
- 2 large yellow onions, thinly sliced
- 2 tablespoon unsalted butter
- ½ cup sour cream
- 2 tablespoon prepared horseradish
- 1 tablespoon fresh chives, finely chopped
- Salt and freshly ground black pepper, to taste
Instructions
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1Preheat oven to 400°F (200°C). Brush baguette slices with olive oil on both sides, place on a baking sheet, and toast for 8-10 minutes until golden and crisp.
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2Meanwhile, melt butter in a large skillet over medium heat. Add onions and cook, stirring occasionally, for 15-18 minutes until caramelized. Season with salt and pepper and set aside.
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3Season steak with salt and pepper. Heat 1 tablespoon olive oil in a skillet over high heat. Sear steak 2-3 minutes per side for medium-rare, or to desired doneness. Let rest 5 minutes, then slice thinly against the grain.
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4In a small bowl, mix sour cream, horseradish, and chopped chives. Season with a pinch of salt and pepper.
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5To assemble, spread a small amount of horseradish sauce on each crostini. Top with a slice of steak, a spoonful of caramelized onions, and garnish with extra chives if desired. Serve immediately.
Approximate Information for One Serving
Nutrition Disclaimers
Number of total servings shown is approximate. Actual number of servings will depend on your preferred portion sizes.
Nutritional values shown are general guidelines and reflect information for 1 serving using the ingredients listed, not including any optional ingredients. Actual macros may vary slightly depending on specific brands and types of ingredients used.
To determine the weight of one serving, prepare the recipe as instructed. Weigh the finished recipe, then divide the weight of the finished recipe (not including the weight of the container the food is in) by the desired number of servings. Result will be the weight of one serving.
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