Step 1: Pre-heat your oven to 350°F (175°C). Lightly grease a standard 9-inch (≈23 cm) pie dish or quiche pan. You’ll want to make sure every nook and cranny is coated to prevent sticking and ensure easy removal later.

Step 2: Heat 1 Tbsp of the oil in a large skillet over medium-high heat. Add the zucchini rounds and brown them on each side, then remove and set aside. This step is crucial for developing flavor – don’t skip it! Browning the zucchini prevents it from becoming watery in the finished quiche and adds a lovely caramelized taste.

Step 3: Reduce the heat to medium, add the remaining 1 Tbsp oil, and sauté the onion until translucent. Stir in the garlic and cook 1 minute more. Add the spinach and cook until just wilted. You want the spinach to wilt down significantly, which will happen quite quickly!

Step 4: Evenly spread the onion-spinach mixture in the prepared pan. Arrange the browned zucchini rounds in a single layer, then top with half the tomato slices. Sprinkle the minced basil over the vegetables. This layering technique ensures that every bite contains a variety of flavors and textures!

Step 5: In a mixing bowl, whisk together the eggs, dairy-free milk, salt, and pepper. Pour the custard evenly over the layered vegetables. Finish by arranging the remaining zucchini rounds and tomato slices on top. This top layer of vegetables will create a beautiful presentation as the quiche bakes.

Step 6: Bake for 35 40 minutes, or until the center is set and lightly golden. You’ll know it’s done when the edges are golden brown and the center doesn’t jiggle when you gently shake the pan. A knife inserted into the center should come out clean.

Step 7: Let the quiche cool briefly before slicing into wedges. This resting period is important as it allows the quiche to set completely, making it easier to slice cleanly. Garnish with additional fresh basil before serving to add a pop of color and fresh flavor.