Pumpkin, gruyere and sage quiche with a potato crust

Ingredients

• 600g kent pumpkin, seeds removed and cut into wedges 3-4 cm thick
• Drizzle of olive oil
• Salt and pepper to season
• 450g potatoes
• 2 tablespoons olive oil
• ¼ teaspoon each fine salt and cracked black pepper
• 20g butter
• Small handful fresh sage leaves
• 4 Yallamundi Organic Large Free-Range eggs
• 125ml milk
• Salt and pepper for seasoning
• 80g gruyere cheese, rind removed and cut into cubes