Vermont Mushroom and Delicata Squash Tarts

2 tbsp unsalted butter plus more if needed
2 tbsp canola oil
1 cup chopped onion
10 oz Baby Bella mushrooms, with all but 1/2  inch of stems removed, and mushrooms cut in 1/4- to  1/2- inch dice
1 tsp minced garlic
1 tsp dried crushed rosemary
1/4 tsp Kosher salt plus more if needed
Several grinds of black pepper plus more if needed
3 tbsp grated Parmesan, preferably Parmigiano Reggiano plus 2 tbsp extra for sprinkling over tarts
1/4 cup crème fraîche plus 2 tbsp extra for the garnish
1 sheet puff pastry from a 17.3 ounce package, defrosted (Pepperidge Farm works well.)
One small Delicata squash (10 to 12 oz), with skin left on, rinsed and dried (See note.)
Olive oil
Fresh rosemary sprigs for garnish

1.Arrange a rack at center position and preheat oven to 400 degrees F. Have ready a baking sheet for the tarts.

2 Melt 1/2 tablespoon each of butter and oil in a medium skillet over medium heat.  When hot, add the onions and sauté, stirring often, until softened and lightly browned, about 5 minutes. Add remaining butter and oil and when hot, add the diced mushrooms, garlic, dried rosemary, 1/4 teaspoon salt, and several grinds of pepper. Cook, stirring, until mushrooms are tender, about 5 minutes. If needed, add up to 1 tablespoon extra butter. Remove from heat and cool about 2 minutes. Then stir in 3 tablespoons of Parmesan and 1/4 cup crème fraîche. Taste and season with more salt and pepper if needed. Set aside.

3.Halve the squash, lengthwise. With a teaspoon scrape out and discard the membranes and seeds from each half. With a sharp knife, cut 12 thin 1/8-inch-thick slices from one of the halves and halve these rainbow-shaped slices by cutting vertically through the top center of each so that you have 24 slices. (Save extra squash for another use.) Set aside.

4.Place puff pastry sheet on a lightly floured work surface, and with a rolling pin, gently flatten the seams. Cut sheet into four equal squares. With a sharp knife, lightly score a 3/4- inch border around the inside edge of each pastry square, taking care not to cut all the way through the dough. (You simply want to trace a frame within each square, which will rise around the filling and form the sides of each tart.) Transfer squares to a baking sheet. (Squares can be prepared 2 hours ahead; cover and refrigerate.)

5.Divide mushroom mixture evenly and mound within borders of each square. Brush the squash slices on both sides with some olive oil and season them with salt and pepper. Arrange 6 on top of each tart, tucking them slightly into the filling. Bake tarts until sides have puffed and are golden brown and filling is hot, 20 to 25 minutes. Watch carefully.

6.Garnish each tart with a dollop of crème fraîche and a fresh rosemary sprig.

Serves 4

Note:  Delicata squash works particularly well in this recipe. However, if you can’t find it, you can omit it and garnish the tarts simply with a dollop of crème fraîche and a fresh rosemary sprig.

Copyright Betty Rosbottom 2025