If you eat gluten, puff pastry might be one of the best things to keep in your freezer all of the time. You can make an elegant vegetarian main dish with whatever vegetables you have in your fridge. This one was made with Delicata squash, onions, garlic, and fennel. And because I had a knob of Parmesan in my fridge, I added it to the top, but definitely not necessary.
Preheat oven to 375 degrees. In a skillet, warm olive oil. When hot, add onion and garlic. Saute until glistening, about 3 minutes. Add fennel and saute until all the vegetables are just beginning to brown.
When vegetables are cooking, cook Delicata squash for about 25 minutes in oven. Just place squash cut side up with a little olive oil rubbed on top and sprinkle of salt. You could just add it to the vegetable saute on the stove, but I like the browned flavor from oven roasting the squash.
Once the squash is cooked, cut in half moons and set aside.
Roll out puff pastry to fit your pan. My preference is to use parchment paper for nearly every pan I use rather than cooking directly on the metal -- it's easier to clean up and I like how I slide off the pastry onto a cutting board to easily cut. I use a half-sheet cake, but you can also make in a tart pan or even a pie plate. After the pastry has been placed in the desired pan, place squash rounds on top, followed by onion/garlic/fennel saute.
Top with a sprinkle of your favorite salt and grated Parmesan cheese (if desired), and cook for about 20 minutes until the crust has puffed and the edges are browned.