Steps
1. Preheat your oven to 375°F (190°C).
2. In a bowl, whisk together the egg, milk, sugar, vanilla essence, and a pinch of salt and pepper.
3. Add the finely chopped onion and oats to the mixture, stirring until well combined.
4. Place the chicken breast in a baking dish, skin side up, and pour the oat mixture over the top.
5. Sprinkle the grated cheddar cheese evenly over the chicken and oat mixture.
6. Bake in the preheated oven for 30-35 minutes, or until the chicken is cooked through and the cheese is bubbly and golden.
7. Let it rest for a few minutes before serving.