In a bowl, combine the flour and grated almonds. Add the milk and stir for 1-2 minutes until smooth.
Separate the eggs into yolks and whites. Stir the egg yolks into the batter and season with salt and pepper.
Using an electric mixer or whisk, beat the egg whites on high speed for 3-5 minutes until stiff peaks form. Gently fold them into the batter until just combined.
Cut the chorizo into 1 cm thick slices. Place the slices in a baking dish and pour the batter over them. Sprinkle the grated Gruyère on top.
Bake in a preheated oven at 180°C (356°F) for 30 minutes until golden.