1
Preheat oven to 400°F.
2
Toss diced squash in medium bowl with 1 tbsp oil and season lightly with salt and pepper to taste. Make sure squash is evenly coated. Place on parchment lined baking tray and roast for 30 min. Reduce oven to 375°F once done.
3
While squash is roasting, caramelize the sliced onions. Add onions to a large pan and sauté with 1 tbsp oil over medium heat. Stir every few minutes with flat spatula to ensure onions don't burn to pan. Once onions turn translucent, drizzle balsamic vinegar (or save and drizzle after pie cookies for a less brown pie) on onions and continue to stir every couple minutes. Once onions are dark and caramelized to your liking remove from heat and cool.
4
In a large bowl whisk eggs, milk, lemon juice, spices and herbs together. Fold in squash, caramelized onions and feta.
5
Take pie shells out of freezer and place on cookie sheet. If using par-baked shell, make sure to check pie after 30 minutes of baking time. If the edges look too dark, cover edges with foil to prevent burning.
6
Pour mixture into pie shells evenly and bake at 375°F for 45 minutes until pie is firm. Let cool for 10 minutes before slicing and enjoy!