Preheat your oven to 375°F (190°C).

In a large skillet, heat a tablespoon of olive oil over medium heat. Add diced onion, sliced mushrooms, and cubes of butternut squash, sautéing for 5-7 minutes until tender.

Stir in chopped kale and cook for an additional 2-3 minutes until wilted. Let the mixture cool slightly.

In a mixing bowl, whisk together the eggs, milk, salt, and pepper until well combined and slightly frothy.

Spread the sautéed vegetable mixture evenly in your pre-made pie crust, then pour the egg mixture over the vegetables.

Sprinkle shredded cheese over the top of the quiche.

Bake the quiche in the preheated oven for 35-40 minutes until golden brown and set.

Allow the quiche to cool for 5-10 minutes before slicing and serving.