Sprinkle salt and pepper over the chicken breasts. Make sure both sides are covered well. This helps the meat stay flavorful during the cooking process.

Heat oil and butter in your large pan. Fry the chicken until it turns golden brown. Remove the chicken from the pan and set it aside on a plate.

Add the chopped bacon to the same pan. Fry until the bacon is crispy and fat melts. Throw in the sliced onions and cook until they are soft.

Push the bacon and onions to the side. Add the apple slices to the pan. Cook them for two minutes until they start to soften and turn brown.

Pour the apple cider into the hot pan slowly. Use a spoon to scrape the tasty brown bits from the bottom. Let the liquid bubble and reduce slightly.

Stir in the double cream and the wholegrain mustard. Add the chopped sage for a fresh herb flavor. The sauce should look rich, pale, and very creamy.

Place the browned chicken breasts back into the sauce. Turn the heat down to low. This allows the chicken to cook through without making the cream break.

Let everything simmer gently for about 10 to 12 minutes. Check that the chicken is cooked through and no longer pink. The sauce should be thick and glossy.