Description
Caramelized Onion & Mushroom Crostini is a simple yet elegant appetizer that combines sweet caramelized onions, earthy mushrooms, and creamy cheese on crispy baguette slices. Perfect for entertaining, holidays, or cozy nights in, this vegetarian-friendly crostini delivers rich flavor and gourmet appeal with minimal effort.
Ingredients
Scale
Ingredients:
- 1 French baguette, sliced into ½-inch rounds
- 2 tbsp olive oil (plus more for drizzling)
- 2 large yellow onions, thinly sliced
- 2 cups (225 g) cremini or button mushrooms, sliced
- 2 tbsp butter
- 1 clove garlic, minced
- Salt and freshly ground black pepper to taste
- 1 tsp fresh thyme leaves (or ½ tsp dried thyme)
- ½ cup grated parmesan or crumbled goat cheese (optional)
- 1 tbsp balsamic glaze for drizzling (optional)
Instructions
- Caramelize the Onions: Heat 1 tbsp olive oil and 1 tbsp butter in a skillet over medium-low heat. Add onions and a pinch of salt. Cook for 25–30 minutes, stirring occasionally, until golden and caramelized.
- Sauté the Mushrooms: Add remaining butter and olive oil to the skillet. Stir in mushrooms, garlic, thyme, salt, and pepper. Cook 7–10 minutes until browned. Combine with the caramelized onions.
- Toast the Crostini: Preheat oven to 400°F (200°C). Arrange baguette slices on a parchment-lined baking sheet. Brush with olive oil on both sides and bake 8–10 minutes, flipping halfway through, until crisp and golden.
- Assemble the Crostini: Spoon the onion-mushroom mixture onto each toasted slice. Top with parmesan or goat cheese if desired. Return to the oven for 5 minutes to warm through.
- Finish and Serve: Arrange on a platter, drizzle with balsamic glaze, and garnish with fresh thyme or parsley. Serve warm and enjoy!
Notes
- Patience is key: Slow caramelization ensures rich, sweet onions without bitterness.
- Use fresh mushrooms: Avoid canned varieties for better texture and flavor.
- Toast just before serving: Keeps the crostini crisp.
- Add balance: A touch of balsamic glaze or honey elevates the savory flavor.
- Make-ahead tip: Caramelize onions in advance and store up to 4 days in the fridge.
- Prep Time: 20 minutes
- Cook Time: 30 minutes
- Category: Appetizer
- Method: Baked
- Cuisine: Italian
Nutrition
- Serving Size: 1 crostini
- Calories: 110
- Sugar: 2g
- Sodium: 150mg
- Fat: 6g
- Saturated Fat: 2g
- Unsaturated Fat: 3g
- Trans Fat: 0g
- Carbohydrates: 10g
- Fiber: 1g
- Protein: 3g
- Cholesterol: 8mg
Keywords: Caramelized Onion & Mushroom Crostini, Mushroom Crostini, Onion Crostini, Vegetarian Appetizer, Party Finger Food, Italian Appetizer