Portobello & Onion Tart Recipe

Preheat oven to 400 °. Unfold puff pastry onto a parchment paper-lined baking sheet. Using a sharp knife, score a 1/2" border along edges of pastry. Within border, prick pastry with a fork. Bake 8-10 minutes or until golden brown. Remove from oven. If center has puffed, flatten gently with a spatula. Meanwhile, in a large skillet, heat 1 tablespoon oil over medium-high heat. Add mushrooms; cook and stir 4-5 minutes or until lightly browned. Remove from pan. To same pan, add remaining oil and the onion; cook and stir 2-3 minutes or until lightly browned. Return mushrooms to pan; stir in salt. In a small bowl, whisk eggs until blended; stir in cheese. Pour into crust. Top evenly with mushroom mixture. Bake 13-15 minutes or just until cheese mixture is set. If desired, sprinkle with rosemary.