Thinly sliced onions and chunky mushrooms caramelize with butter and Marsala wine to make the perfect jammy topping for this easy crostini appetizer with a silky sweet taste.
This recipe is brought to you by Vermont Creamery
Carmelized onions and mushrooms are my jam. Literally. Jammy. Because that’s what happens when the sugars of these two basic ingredients hit the heat and do their dance with sweet cultured butter. The sugars bloom and the onion and mushroom’s earthy flavors deepen to create a savory jam that becomes nearly as sweet as any preserve you’ll spread on toast.
That’s what makes this mixture the perfect topping for hand-held toasted crostini appetizers. And they are super easy to prep and cook too. Let’s party!
What’s In Onion and Mushroom Crostini
Crostini are one of the most versatile appetizers you’ll find on the party table—and one of the most popular. Known in Italian as “little toasts”, crostini are thin slices of toasted bread topped with a wide array of savory toppings.
This appetizer recipe combines two of my favorite toppings—caramelized onions and caramelized mushrooms—into one jammy relish to serve at holiday parties and potlucks. A few other ingredients add to deepen their flavor, including:
- Yellow onion
- Brown or button mushrooms (known as baby bella mushrooms, too)
- Garlic
- Vermont Creamery Cultured Butter
- Fresh thyme leaves
- Marsala wine
- Kosher salt
- Black pepper
- Sourdough or French bread baguette
Butter Brings Out the Caramelized Jam
If there ever was a scent that signaled the tastebuds to prepare for deliciousness, it would be sizzling butter melting into onions and mushrooms. Butter is what coaxes onions to become tawny gold and feeds thirsty mushrooms the butterfat they need to soften and absorb flavor.
Vermont Creamery Cultured Butter is a butter of a higher standard. What sets their cultured butter apart from the rest is the process. Making cultured butter is like making fine wine, where fermenting the cream as you would grapes for wine—slowly—produces the best flavors. The longer the culture, the better, where after fermenting, wonderful notes of buttermilk and hazelnuts develop in the butter cream for a creamy, delicious flavor.
I used Vermont Creamery Cultured Butter unsalted in this recipe, but their Cultured Butter with Sea Salt works wonders too.
