Preheat the oven to 356°F / 180°C
Place the vegetables in an ovenproof bowl or tin. Set aside
Make the sauce by melting the butter in a pot over medium heat.
Stir in the flour, ground black pepper, salt and dried chilli flakes if using. SEE NOTE 3
Cook, whisking continuously for 2 minutes or until thick and bubbling. Gradually stir in the milk. Whisk until the sauce thickens slightly. Remove from heat. SEE NOTE 4
Add in half of the grated cheese and whisk until melted.
Gently stir the sauce into the vegetables and top with the remaining cheese.
Bake in the oven at 356°F / 180°C for about 15 to minutes until the cheese is melted and the vegetables are cooked to your preference.·