Creamy, cheesy mushroom and potato bake

Ingredients

• 3 garlic cloves, crushed
• 1 leek, sliced
• 1 tbsp butter
• 5 large flat mushrooms, roughly chopped
• 7 swiss brown mushrooms, roughly chopped
• 4 sprigs of fresh thyme
• 1 & 1/4 cups thickened cream
• 1 tbsp powdered vegetable or chicken stock
• 2 large sweet potatoes, peeled & sliced
• 5 large potato, peeled & sliced
• 1 cup pecorino cheese, grated
• 1 cup tasty cheese, grated
• Salt
• pepper
• Parsley, roughly chopped