Step 1

In a medium oven-proof skillet heat the olive oil, add the garlic and cook until softened.

Step 2

In a glass or metal bowl, beat the egg whites until stiff peaks form. In another bowl, beat the egg yolks and stir in the spinach and ricotta cheese; season with the salt, pepper and nutmeg. Fold in the egg whites.

Step 3

Pour the mixture into the hot skillet and cook over medium heat until just set around the edges, about 2 minutes.

Step 4

Transfer the frittata to the oven and bake at 200°C until golden and fluffy, about 15 minutes.

Step 5

Sprinkle the Grana Padano all over the top and bake for 2 minutes.

Step 6

Cut into wedges and serve immediately.