Preheat your oven to 350°F (176°C).

Roll out your premade pie crust and fit it into a 9-inch pie plate.

Trim the woody ends off the asparagus and slice into ¼-inch pieces.

In a skillet, heat olive oil over medium-high heat, sauté minced garlic for about 30 seconds, then add chopped asparagus and cook for about 3 minutes.

Add baby spinach to the skillet and cook until wilted, about 2-3 minutes.

Spread the sautéed spinach and asparagus mixture in the prepared pie crust.

Whisk together eggs, whole milk, half of the Gruyère cheese, sea salt, and black pepper in a mixing bowl.

Pour the egg mixture over the vegetable layer in the pie crust and sprinkle the remaining Gruyère cheese on top.

Bake the quiche in the preheated oven for 45-50 minutes until the center is set and crust is golden brown.

Let the quiche cool for about 5 minutes before slicing and serving warm or at room temperature.