Preheat the oven:
Preheat your oven to 350°F (175°C). Liberally grease a pie dish or quiche pan with ghee or avocado oil.
Cook the zucchini:
Heat 1 tablespoon of your chosen fat in a large skillet over medium-high heat. Arrange the zucchini rounds in a single layer and cook until they start to brown, about 2-3 minutes. Flip the rounds and cook the other side. Once browned, remove them from the pan.
Sauté the onions and spinach:
Lower the heat to medium and add the remaining tablespoon of fat to the skillet. Add the chopped onions and cook until translucent and starting to brown (about 3-4 minutes). Add minced garlic and cook for another minute. Stir in the baby spinach and cook until just wilted. Remove from heat.
Assemble the quiche:
Spread the onion-spinach mixture evenly on the bottom of the greased quiche pan. Layer the cooked zucchini rounds and tomato slices on top, reserving a handful of each for the top layer. Sprinkle the minced basil evenly over the vegetables.
Prepare the egg mixture:
In a large bowl, whisk together the eggs, dairy-free milk, salt, and pepper. Pour this mixture over the vegetables in the quiche pan, then gently shake the pan to settle the ingredients. Top with the remaining zucchini rounds and tomato slices.
Bake:
Place the quiche in the preheated oven and bake for 35-40 minutes, or until the center is set.
Cool and serve:
Allow the quiche to cool slightly before slicing into wedges. Garnish with extra fresh basil before serving.
Enjoy your delicious Crustless Garden Vegetable Quiche!