Preheat the oven to 350°F (175°C) and grease a pie dish or quiche pan with ghee or avocado oil.

In a large skillet, heat 1 tablespoon of oil over medium heat. Add the sliced zucchini and sauté for about 5–7 minutes until golden brown and tender.

Lower the heat and add the remaining oil to the skillet. Sauté the onion for around 3–4 minutes until translucent, then add minced garlic and cook for an additional minute.

Add baby spinach and cook just until wilted, about 1–2 minutes, then remove from heat.

Spread the spinach and onion mixture evenly across the bottom of the quiche pan, layer the sautéed zucchini on top, followed by sliced tomatoes, and sprinkle with minced basil.

In a mixing bowl, whisk together eggs, dairy-free milk, salt, and pepper until combined and slightly frothy. Pour over the layered vegetables.

Bake in the preheated oven for 35–40 minutes, or until the center is set and the top is golden. Let cool slightly before slicing.

Garnish with reserved fresh basil before serving. Serve warm or at room temperature.