Trim zucchini ends and slice on an angle into ½" rounds. Cut sun-dried tomatoes into ¼" dice. Coarsely chop crispy fried onions. Pat chicken breasts dry, and season both sides with ¼ tsp. salt and ¼ tsp. pepper.

Place a large non-stick pan over high heat and add 2 tsp. olive oil. Add zucchini to hot pan and stir often until browned but still crunchy, 2-3 minutes. Remove from burner and stir in sun-dried tomatoes, ¼ tsp. salt, and a pinch of pepper.

Place casserole dishes on prepared baking sheet to catch any drips. Transfer zucchini mixture to casserole dishes. Wipe pan clean and reserve. In each dish, pour 1 Tbsp. cream (reserve remaining for sauce) over zucchini mixture and top with Parmesan. Bake in hot oven until golden brown, 8-12 minutes. Rest baked gratin 5 minutes, then top with crispy onions. While gratin bakes, cook chicken.

Return pan used to cook zucchini to medium-high heat and add 2 tsp. olive oil. Add chicken breasts to hot pan and cook undisturbed until browned, 3-5 minutes. Flip chicken, reduce heat to medium, and cook until chicken is browned and reaches a minimum internal temperature of 165 degrees, 4-6 minutes. Remove chicken to a plate and rest 3 minutes. Reserve pan; no need to wipe clean.

Return pan used to cook chicken to medium-high heat. Add 2 Tbsp. water, reserved cream, and any accumulated juices from resting chicken. Bring to a boil. Remove from burner. Stir in Dijon and a pinch of salt. Sauce will thicken as it cools. Plate dish as pictured on front of card, garnishing chicken with sauce. Serve gratin on a plate or in casserole dish. Bon appétit!