Preheat the oven to 360°F (180°C).

Rinse the quinoa under cold running water for about 1-2 minutes. Drain well.

Combine the rinsed quinoa with 3 cups of vegetable stock or water in a saucepan. Bring to a boil, then reduce to a simmer and cover. Cook for about 15 minutes.

In a large baking dish, mix together the cooked quinoa, sun-dried tomato pesto, Greek yogurt, mozzarella, feta, spinach, chopped sun-dried tomatoes, sliced onion, and Italian seasoning. Adjust with more stock if too dry.

Sprinkle remaining mozzarella on top, cover tightly with aluminum foil, and bake for 30 minutes.

Remove from oven, uncover, and sprinkle additional feta and sun-dried tomatoes on top. Garnish with fresh basil before serving.