Rinse the chicken breast fillets under cold running water and pat dry. Season both sides with salt and pepper. Place them side by side in a greased baking dish.
In a bowl, mix the French dressing, lingonberries, whipped cream, and the contents of the onion soup sachet. Pour the mixture over the chicken fillets.
Preheat the oven to 180°C (356°F) with conventional heating (top and bottom elements) OR 160°C (320°F) with fan/convection heating.
Place the baking dish on the middle oven rack and bake for about 60 minutes, until the chicken reaches an internal temperature of 74°C (165°F).