Preheat your oven to 375°F (190°C).

In a large skillet, pour in olive oil over medium heat. Add diced onion, mushrooms, and butternut squash, sauté for 5-7 minutes, stirring frequently.

Stir in chopped kale and continue cooking for an additional 2-3 minutes until wilted.

In a medium bowl, whisk together eggs and milk until frothy. Add salt and pepper to taste.

Spread sautéed vegetable mixture into the pie crust and pour egg mixture over it. Top with shredded cheese.

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

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