Cook diced bacon in a pan over medium-high heat for 5 minutes until crispy. Add breadcrumbs and toast for 2 minutes until golden. Set aside.
Slice the chicken breast fillets and season with salt and pepper. Fry in a pan over medium-high heat with 3 tablespoons of oil for 4 minutes until golden. Pour in the chicken broth and cooking cream, bring to a boil, then reduce heat to medium-low, cover, and simmer for 3 minutes.
While the chicken simmers, blanch the cauliflower in plenty of boiling salted water for 3 minutes. Drain well. Stir the sauce thickener into the hot sauce with the chicken, then season with salt and mustard.
Add the cauliflower to the sauce, stir to combine, and heat over medium-low heat for 3 minutes without boiling. Check that the chicken has reached 74 °C / 165 °F internally. Serve sprinkled with the bacon breadcrumb mixture.