Pour the breadcrumbs onto a large baking tray and coat with oil spray. Place in the oven at 180C/350F for around 5 minutes until light golden. Pour them into a bowl to cool and increase oven temperature to 200C/400F.

Carefully slice a pocket into the side of each chicken breast. Place two slices of cheese on top of two slices of ham and tightly roll. Wedge into the pocket and close it over to cover the filling. Use toothpicks to seal the seam shut.

In a small bowl, combine paprika, salt, onion powder, garlic powder, black pepper, and cayenne pepper.

Line up 3 bowls: the first with flour and half of the seasoning, the second with beaten egg, and the last with the toasted breadcrumbs and remaining seasoning. Dredge the chicken through each bowl, fully coating at each stage.

Line a baking tray with foil and place a wire rack on top. Spray the rack with oil, place the chicken on top, spray the chicken with oil, and place in the oven for 25-30 minutes until deep golden & crispy, with the cheese starting to leak out. Ensure the chicken is piping hot and white through the center.

In a medium-sized pot over medium heat, melt the butter. Stir in the stock, cream, parmesan, mustard, and white pepper until blended, then bring to a gentle simmer. Simmer for 5-6 minutes, stirring frequently, until the sauce thickens. Adjust with salt if needed, then remove from heat.

Carefully remove the toothpicks from the chicken, then serve with the sauce.