Save to Pinterest The first time I brought a butter board to a dinner party, my friend Sarah actually laughed out loud. She said I was putting softened butter on a cutting board and calling it hors d'oeuvres. But then she took a bite of those caramelized onions folded into creamy butter, and I watched her face change completely. Suddenly everyone was crowded around the board, knives scraping, bread disappearing, and the evening shifted from polite conversation to something much warmer.
Last autumn, my kitchen filled with that unmistakable scent of onions slowly turning golden, and my roommate wandered in from her room with wide eyes. She ended up eating half the onions straight from the pan before I could even mix them into the butter. Now whenever I make this recipe, I always caramelize a few extra onions because apparently snacking during prep is part of the tradition.
Ingredients
- 2 large yellow onions, thinly sliced: Yellow onions have the perfect balance of sweetness and bite that transforms during slow cooking
- 2 tbsp unsalted butter: Starting the onions in butter builds that rich foundation flavor
- 1 tbsp olive oil: Prevents the butter from burning while giving you enough fat to properly caramelize
- 1/2 tsp kosher salt: Draws moisture out of the onions so they can brown instead of steam
- 1/2 tsp sugar: Helps the onions develop that deep amber color without requiring extra time
- 1/4 tsp freshly ground black pepper: Adds a subtle warmth that cuts through all that richness
- 250 g (8 oz) unsalted butter, softened: Room temperature butter blends smoothly into the most spreadable texture
- 1/2 tsp flaky sea salt: Those crunchy salt crystals are the surprise that makes every bite interesting
- 1 tbsp fresh chives, finely chopped: Their mild onion flavor bridges the gap between fresh and cooked
- 1 tsp fresh thyme leaves (optional): Adds a little earthy complexity that makes the butter taste more sophisticated
Instructions
- Melt the butter and oil together:
- Combine the 2 tablespoons butter and olive oil in a large skillet over medium heat until they shimmer and meld together
- Add the onions and seasonings:
- Toss in the sliced onions, kosher salt, and sugar, then stir until every strand is coated in fat
- Start the slow cook:
- Let the onions cook over medium heat, stirring every few minutes, as they begin to wilt and turn translucent
- Wait for the magic:
- Continue cooking for 35 to 40 minutes, stirring occasionally, until the onions turn deep golden brown and smell impossibly sweet
- Season and cool the onions:
- Sprinkle with black pepper, then spread them on a plate to cool completely while you prepare the butter
- Mix the base butter:
- In a medium bowl, combine the softened butter with half the caramelized onions, sea salt, chives, and thyme until everything is evenly distributed
- Spread onto your board:
- Scoop the butter mixture onto a large cutting board or platter and use the back of a spoon to spread it into an even layer with gentle swirls
- Top with remaining onions:
- Spoon the rest of the caramelized onions over the butter, then finish with extra flaky salt, more herbs, and freshly ground black pepper
- Serve immediately:
- Set out the board with crackers and baguette slices and watch it disappear faster than you expected
Save to Pinterest After I served this at my sister's book club meeting, she called me the next day asking for the recipe. Apparently the conversation kept circling back to that butter board instead of the actual book. Sometimes food is just the catalyst that gets people talking.
Making Ahead
I've learned that caramelized onions actually taste even better after a night in the refrigerator. You can cook them up to three days ahead and store them in an airtight container. The butter mixture can be made a day in advance, but let it soften at room temperature for about 30 minutes before spreading.
Serving Suggestions
While baguette slices and crackers are classic, I've discovered this butter works beautifully on roasted potato rounds, thick slices of toasted sourdough, or even folded into warm dinner rolls. The contrast of hot bread against the cool, onion-studded butter creates something special.
Flavor Variations
Once you master the basic technique, the variations become endless. A splash of balsamic vinegar in the last five minutes of caramelizing creates incredible depth, or try swapping in shallots for a milder, sweeter onion flavor.
- Stir in grated Parmesan for an extra savory kick
- Add minced garlic during the last ten minutes of onion cooking
- Mix in crispy bacon bits just before serving for texture
Save to Pinterest There is something deeply satisfying about turning humble ingredients into something that makes people gather around. That is the kind of cooking I want to keep doing.
Common Recipe Questions
- → How far in advance can I make this?
You can caramelize the onions up to 3 days ahead and store them refrigerated. The butter mixture can also be prepared 1-2 days in advance and kept chilled. Bring to room temperature before spreading for best texture.
- → Can I use salted butter instead of unsalted?
Yes, simply reduce or omit the additional salt called for in the recipe. Taste as you mix to ensure the seasoning is balanced without becoming too salty.
- → What other herbs work well in this?
Fresh parsley, rosemary, or sage make excellent alternatives or additions to chives and thyme. Each brings a slightly different aromatic profile that complements the sweet-savory onions.
- → How do I prevent the onions from burning?
Keep the heat at medium or medium-low and stir frequently. If onions start browning too quickly, reduce heat immediately and add a splash of water or broth to deglaze the pan.
- → Can I make this dairy-free?
Use a high-quality vegan butter substitute and coconut oil or olive oil for caramelizing. The texture will be slightly different but still delicious for dairy-free guests.
- → What's the best way to serve this?
Set out the board at room temperature with an assortment of crackers, sliced baguette, bread sticks, or even apple slices for contrast. Let guests spread it themselves for an interactive element.