Heat 1 tablespoon of olive oil in a pan over medium heat. Add the sliced onions and sauté until tender, about 10-15 minutes.
Reduce heat, add ¼ cup of water, cover, and cook the onions until caramelized, approximately 50 minutes, stirring occasionally.
Meanwhile, toss the pumpkin chunks with olive oil, salt, and pepper. Roast in a preheated 350°F (180°C) oven for 30-40 minutes or until tender. Set aside.
Brush a sheet of phyllo dough with olive oil and fit it into a greased 9-inch pie dish, leaving ends overhanging. Repeat with the remaining phyllo sheets, layering them.
Filling and Baking
In a bowl, mix together the caramelized onions, roasted pumpkin, eggs, half and half, gorgonzola, and sage.
Pour the mixture into the prepared phyllo crust.
Bake the quiche in a preheated 375°F (190°C) oven for 25-45 minutes, or until golden brown and set in the center.
Notes
Best served warm or at room temperature. Pairs well with a mixed green salad. Leftovers can be stored in an airtight container in the fridge for up to 3 days. Can also be frozen before baking for up to 2 months.