4 large cooked chicken breasts
15g/½oz/1 tbsp butter
1 tbsp plain (all-purpose) flour
125ml/4fl oz/1 cup milk
175g/6oz/1½ cups grated Cheddar or Gruyère
25g/1oz/½ cup fresh white breadcrumbs
1 tsp wholegrain mustard
1 medium (US large) egg yolk
4 x cherry tomatoes on the vine
1 Melt the butter in a pan over a low heat, then stir in the flour and cook for 1 minute. Gradually add the milk, stirring until the mixture thickens to a smooth sauce.
2 Add the cheese, breadcrumbs and mustard to the sauce and cook for 1 minute. Cool a little, then beat in the egg yolk. Preheat the grill (broiler) to medium-high.
3 Preheat the grill (broiler). Spread the paste evenly over each chicken breast and place them in a flameproof dish, then grill (broil) for 2–3 minutes until golden brown.
4 Meanwhile, grill the cherry tomatoes until starting to soften and char. Serve with the hot chicken rarebits.