Pumpkin, ricotta and parmesan frittata

Ingredients

• 1 tablespoon olive oil
• 600 gram butternut pumpkin, peeled, chopped into small cubes
• 1 medium (170g) red onion, cut into thin wedges
• 1 clove garlic, crushed
• 6 eggs
• 2 tablespoon milk
• 1/4 cup finely chopped fresh chives
• salt and freshly ground black pepper
• 200 gram ricotta cheese
• 3/4 cup (60g) finely grated parmesan cheese