Have You Ever Met a Crostini You Didn’t Like?
Alright, confession time: The first time I made these Steak Crostini with Horseradish Sauce & Caramelized Onions, I was convinced they’d be way fancier than my skills (and patience). Turns out, they weren’t hard at all—they’re actually the one thing I don’t mess up at the holidays. Well, except for the one time I got distracted yapping with my cousin and basically charred the bread. Pro tip: Don’t try to swap stories and broil at the same time. But even then, everyone ate them. If that’s not holiday magic, I don’t know what is.
Why You’ll Love This (And Why My Family Can’t Get Enough)
I make these every Christmas Eve because my family is obsessed (I wish I was exaggerating) with that tangy horseradish kick against juicy steak, and the caramelized onions—honestly, it’s like fancy pub food meets party snack. Plus, it’s the one appetizer that gets my uncle to stop talking about his fantasy football league for five minutes. And if you’re the type (like me) who sometimes forgets to actually set the timer, these are ultra-forgiving. Oh, I’ve definitely undercooked the onions once or twice. Still ate them, no regrets.
What You’ll Need (And What I Substitute When I’m Out Of Stuff)
- 1 baguette (or, if I’m in a pinch, ciabatta works fine—I’ve never had anyone complain)
- 300 to 400g steak, preferably sirloin or ribeye (honestly, flank steak is good too, and easier to slice thin)
- 2 large onions, yellow or white—I’ve used red onions once, turned out sweeter but not bad
- 2 tbsp olive oil (or butter, or whatever you’ve got… Gran liked to use schmaltz, but that’s a story for another day)
- 3 tbsp prepared horseradish (I use the jarred stuff, though making it from scratch is, like, a whole thing)
- 125g sour cream (sometimes I’ll do half Greek yogurt if it’s what’s in the fridge)
- Salt and pepper (my measuring is more of a vibe than a science here)
- Chives or parsley for garnish (totally optional, but it does look nice. Sometimes I just throw on a bit of arugula, too)
Let’s Make It (aka, where the magic happens and I spill onions…every single time)
- Slice and toast the bread: Preheat your oven to about 200°C (or 400°F if you swing that way). Slice your baguette on the diagonal—makes it look posh, I think. Brush or drizzle with olive oil, toss onto a baking sheet, and bake for 8-10 minutes till golen (sometimes I leave them a little pale if I know they’ll sit a while). Watch closely; they go from hero to zero real fast under the grill.
- Caramelize the onions: Slice those onions thin—doesn’t have to be perfect. Get a big pan hot, add oil, and chuck in your onions with a good pinch of salt. Keep your heat medium-low. Stir every so often; mine always stick at least once (that’s the good stuff for flavor, scrape it up). This part takes 25-30 minutes—put on some tunes, or play a podcast. They’ll get jammy and sweet (and yeah, they look a bit mulch-y at the start, but stick with it).
- Cook the steak: I season the steak generously (read: both sides, and maybe a bit on the plate too, whoops). Medium-high pan, bit of oil, then steak hits the pan. Cook until medium rare—3-4 minutes a side for sirloin, but trust your gut more than the clock here. Rest it for at least 5 minutes (I’ve rushed this and regretted it—juices everywhere but in the meat!).
- Mix the horseradish sauce: In a bowl, combine sour cream, horseradish, and a pinch of salt and pepper. Give it a taste—if it doesn’t make your nose tingle just a little, add more horseradish (I usually do, because subtlety isn’t my strong suit).
- Assemble: Here’s the fun part: Take a crostini, slather with horseradish sauce, lay on a few steak slices (as thin as you can manage, not gonna judge), top with a spoonful of onions, and a sprinkle of chives. Repeat till you run out or everyone starts picking at the pile.
Notes Only a Real Home Cook Would Tell You
- If the bread cools down too much, I sometimes give it a 2 minute re-crisp in the oven just before assembling, works like a charm.
- I once tried red onions and balsamic vinegar in the caramelizing stage—not bad, but it sort of overpowered the steak. Maybe skip it if you want the beef to shine through.
Things I Swapped (and One Flop)
- I did try blue cheese instead of horseradish sauce one year (and my dad took three helpings, so, y’know—worth considering if you’re into that vibe).
- Mushrooms for vegetarians work okay—NOT great if left too watery though. Trust me, I found that out after a slightly soggy birthday party tray. Actually, roasted red peppers are better.
Don’t Sweat the Gear
No grill pan? Just use your regular skillet. I’ve even broiled the steak on a baking sheet once when my pan was MIA (cleaning day got slightly out of hand, don’t ask). If you don’t have a pastry brush for oiling the bread, a spoon or your hands totally works—gets a bit messy but hey, it’s a holiday party, right?
How to Store (Though Honestly, No One Leaves Leftovers)
If you somehow end up with leftovers—wrap the crostini separately from the toppings, or they’ll get soggy (speaking from one slightly disappointing lunchbox the next day). Honestly, I’ve never had them last more than a day anyway, but the steak and onions keep fine in the fridge for up to two days.
How We Like to Serve
I usually pile them high on a big wooden board—it looks rustic, and people dive in faster than you can say “save me one.” My cousin dips hers in extra horseradish sauce on the side, which is honestly kind of genius. Sometimes I’ll whip up a kettle of mulled wine too, just because it feels festive. Oh, and a little bowl of olives never hurt anyone.
Pro Tips Learned the Hard Way
- Don’t crowd your pan when cooking the steak—you want that sizzle, not steamed beef. I did this once and regretted it… tasted okay, but looked a bit sad.
- Let the steak rest! Seriously, I skipped this step and ended up with steak juice puddles everywhere—it ruined my nice new dish towel. Whoops.
FAQ—Because People Always Ask Me:
- Can I make these ahead?
Yes, kind of—toast the bread and cook the onions/steak, but assemble last minute or they go soggy. If you check Serious Eats’ crostini guide, they agree—soggy is the enemy. - Does the horseradish sauce keep?
Oh, for sure—I’ve kept it for up to 4 days in the fridge. Actually, it gets a little stronger, which I like. - What if I want it spicier?
Add more horseradish. Or, honestly, a tiny splash of hot sauce isn’t a bad move (am I allowed to say that?). - Help, I don’t eat beef—any workaround?
If you’re game, try roasted portobello mushrooms or thick-sliced zucchini as the main topping. Not a carbon copy, but it’s still delicious.
So there you go; my can’t-fail, party-saving Steak Crostini with Horseradish Sauce & Caramelized Onions superstar. Next time you want to bring the wow factor without the not-so-fun stress, give these a whirl. And, er, try not to eat too many before your guests arrive. Ask me how I know…
Ingredients
- 1 baguette, sliced into 1/2-inch pieces
- 2 tablespoons olive oil
- 1 pound sirloin steak
- Salt and freshly ground black pepper, to taste
- 2 large yellow onions, thinly sliced
- 2 tablespoons unsalted butter
- 1/2 cup sour cream
- 2 tablespoons prepared horseradish
- 1 tablespoon fresh chives, chopped (optional)
Instructions
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1Preheat your oven to 400°F (200°C). Arrange baguette slices on a baking sheet, brush both sides with olive oil, and bake for 8-10 minutes, flipping halfway, until golden and crisp.
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2Meanwhile, in a large skillet over medium heat, melt the butter and add sliced onions. Cook, stirring occasionally, until onions are caramelized and golden brown, about 20-25 minutes. Set aside.
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3Season the steak with salt and pepper. In another skillet over medium-high heat, sear the steak for 3-4 minutes per side for medium-rare, or desired doneness. Let rest for 5 minutes, then slice thinly against the grain.
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4In a small bowl, mix sour cream and horseradish until well combined to make the horseradish sauce.
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5To assemble, spread horseradish sauce on each crostini, top with a slice of steak and caramelized onions. Garnish with chopped 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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