Squash and sweet potato gratin Recipe

• 14 oz (400 g) butternut squash
• 14 oz (400g) sweet potatoes
• 1 onion, sliced
• 2 tbsp olive oil
• 2 eggs
• 3/4 cup heavy cream
• 1 tbsp butter
• 1/2 tsp sweet paprika
• pinch of nutmeg
• 3 oz (80 g) gruyère, shredded
• 3 sprig of parsley, chopped
• salt and pepper

Directions