Caramelized Onion & Mushroom Tart

Prep Time 25 mins
Cook Time 50 mins
Rest Time 10 mins
Total Time 1 hr 25 mins
Cooking Method: ,
Cuisine: ,
Courses: , ,
Difficulty: Intermediate
Cooking Temp: 190  C
Best Season: All Seasons
Description

This Caramelized Onion & Mushroom Tart is a rich, savory, and elegant dish featuring golden slow-cooked onions, earthy mushrooms, and a flaky buttery crust. Perfect for brunch, dinner, or special gatherings, this tart delivers deep flavor with simple, wholesome ingredients.

Ingredients
    For the Tart Crust
  • 1.5 cup all-purpose flour (sifted)
  • 0.5 tsp salt
  • 0.5 cup unsalted butter (cold, cubed)
  • 3 –4 tbsp cold water
    • For the Caramelized Onion Filling
  • • 3 large onions (thinly sliced)
  • • 2 tbsp olive oil
  • • 1 tbsp butter
  • • 1 tsp sugar
  • • 0.5 tsp salt
  • • 0.5 tsp black pepper
    • For the Mushroom Layer
  • • 2 cup mushrooms (sliced, button or cremini)
  • • 1 tbsp olive oil
  • • 2 cloves garlic (minced)
  • • 0.25 tsp salt
  • • 0.25 tsp black pepper
    • For the Creamy Filling
  • • 2 large eggs
  • • 0.75 cup heavy cream
  • • 0.5 cup milk
  • • 0.5 cup grated cheese (cheddar, mozzarella, or a mix)
  • • 0.25 tsp nutmeg (optional)
  • • Salt and pepper to taste
    • Optional Garnish
  • • Fresh thyme or parsley (chopped)
Instructions
    Prepare the Tart Dough
  1. 1
    In a mixing bowl, combine flour and salt. Add cold butter cubes and rub them into the flour using your fingertips until the mixture resembles coarse crumbs. Gradually add cold water and mix until a soft dough forms. Do not overwork the dough. Wrap and refrigerate for at least 20 minutes.
    2. Roll and Pre-Bake the Crust
  2. 2
    Roll out the chilled dough and place it into a tart pan. Press gently into the edges and trim excess. Prick the base with a fork. Line with parchment paper and add baking weights or beans. Blind bake at 190°C for 15 minutes, then remove weights and bake for another 5 minutes until lightly golden.
    3. Caramelize the Onions
  3. 3
    Heat olive oil and butter in a pan over medium-low heat. Add sliced onions, salt, and sugar. Cook slowly for 20–25 minutes, stirring occasionally, until onions turn soft, golden brown, and slightly sweet. Add black pepper and set aside.
    4. Cook the Mushrooms
  4. 4
    In another pan, heat olive oil over medium heat. Add garlic and sauté briefly until fragrant. Add mushrooms, salt, and pepper. Cook until mushrooms release moisture and become golden brown. Remove excess liquid if necessary.
    5. Prepare the Cream Mixture
  5. 5
    In a bowl, whisk together eggs, cream, milk, cheese, nutmeg, salt, and pepper until smooth and well combined.
    6. Assemble the Tart
  6. 6
    Spread the caramelized onions evenly over the pre-baked crust. Layer the cooked mushrooms on top. Pour the creamy egg mixture over the filling, ensuring even distribution.
    7. Bake the Tart
  7. 7
    Place the tart in the oven and bake at 190°C for 25–30 minutes, or until the filling is set and the top is lightly golden.
    8. Rest and Serve
  8. 8
    Remove from oven and let the tart rest for 10 minutes before slicing. Garnish with fresh herbs if desired. Serve warm or at room temperature.
Note
  • Make it lighter: Substitute heavy cream with half-and-half or evaporated milk.
  • Add protein: You can add cooked chicken pieces if desired (halal-friendly).
  • Cheese variation: Use feta or goat cheese for a tangier flavor.
  • Storage: Store leftovers in an airtight container in the refrigerator for up to 3 days.
  • Reheating: Warm in the oven at 160°C for best texture.
  • Crust shortcut: You can use store-bought puff pastry if short on time.
Keywords: savory tart, vegetarian, comfort food, elegant recipe, oven-baked
Read it online: https://petitepanini.com/recipe/caramelized-onion-mushroom-tart/