Steam the vegetables in salted water. Cook for about 5 to 10 minutes until cooked but slightly firm
Make the cheese sauce by melting butter in a pot over medium heat. Stir in flour,nutmeg and garlic powder . Cook, stirring, for 2 minutes or until bubbling. Remove from heat. Gradually stir in milk. Return to heat. Cook, stirring, for 5 minutes or until mixture boils and thickens slightly. Remove from heat.
Stir in just ½ of each of the cheeses meaning use ½ cup cheddar cheese, ¼ cup / mozzarella cheese 1 Tablespoon parmesan .
Season with salt and pepper and peri peri if using.
Drain the steamed vegetables in a colander and place in a lightly buttered ovenproof dish.
Fold in the cheese sauce and top with the remaining half of cheese.
Bake in the oven at 356°F / 180°C for about 10 minutes until the cheese is melted and golden brown. Serve warm