Potato and Vegetable Torte - Potato Nation

Ingredients

• 10 ml (2 tsp) butter
• 80 g Parmesan, freshly grated
• 60 ml (¼ cup) olive oil
• 1 red onion, finely chopped
• 3 baby marrow, sliced
• 4 leeks, sliced
• 3 garlic cloves, finely chopped
• 30 ml (2 tbsp) fresh basil, snipped
• 400 g potatoes, peeled, quartered and boiled
• Salt and freshly ground black pepper, to taste
• 250 g fresh ricotta
• 250 g mascarpone
• 4 large eggs