Preheat your oven to 350°F. While it heats, mince the shallot into fine 1/4-inch pieces and mince the garlic clove. Measure out the ricotta, parmesan, basil, and all seasonings so everything is ready when you need it. I like to do all my prep work before cooking begins so I can move quickly once the pan is hot.

Heat 1 teaspoon butter and 2 teaspoons oil in a 10-inch oven-safe skillet over medium heat. Once the butter is foaming, add the minced shallots and cook for about 5 minutes until they soften and become translucent, stirring occasionally. Add the minced garlic and cook for 30 seconds until fragrant, then add the spinach in handfuls, stirring until completely wilted. Transfer the cooked vegetables to a plate and let them cool to room temperature—this prevents the hot vegetables from scrambling the eggs prematurely.

In a large bowl, crack all 10 eggs and whisk them together until the yolks and whites are fully combined. Add the 8.5 oz ricotta, parmesan, 2 tablespoons of fresh basil, salt, pepper, and nutmeg, then whisk until the mixture is smooth and the ricotta is evenly distributed throughout—don't overmix or you'll create tough eggs. Gently fold in the cooled sautéed vegetables from Step 2 until just combined. I prefer freshly ground pepper here because it adds a more vibrant flavor compared to pre-ground.

Heat the remaining 1.5 teaspoons butter and 1.5 teaspoons oil in the same 10-inch oven-safe skillet over medium heat. Once the butter is foaming, pour in the egg and ricotta mixture from Step 3. Let it cook undisturbed for about 1-2 minutes until the bottom begins to set, then gently stir with a spatula, pushing cooked portions toward the center and allowing uncooked egg to flow to the edges. Smooth the top of the mixture with your spatula.

Transfer the skillet to the preheated 350°F oven and bake for 5-15 minutes until the center is just set and slightly jiggly but no longer looks wet. Rotate the pan halfway through baking for even cooking. The frittata is done when a knife inserted in the center comes out clean or with just a tiny bit of creamy ricotta clinging to it.

Remove the frittata from the oven and let it rest in the skillet for 2 minutes. Top with dollops of the remaining 5 oz ricotta spread across the surface, then tear the fresh basil over the top for maximum aroma and flavor. Serve directly from the skillet or slide onto a cutting board to portion.