Brown chicken lightly in half the butter in skillet and season with salt and pepper. Lay in single layer in greased shallow baking dish. Splash with about 1/4 cup chicken broth. Cover tightly and bake in preheated (350 degree) oven for 20 minutes.
While chicken bakes, heat onion gently in remaining butter in same pan until soft and golden. Rinse, dry and seed chillies. Dice and add to pan with garlic and flour. Stir and cook a minute or so. Stir in the broth (add broth from chicken to measure 1 cup). Stir over low heat until smooth and slightly thickened.
Pour into blender and whirl until pureed (or use submersible blender). Put back in skillet and stir in cream. Heat just to simmering and pour over chicken. Sprinkle with cheese.
Bake in 350 degree oven 25 to 30 minutes, or until chicken is heated through and cheese is glazed.