Adjust rack to top position (top and middle positions for 8 servings) and preheat oven to 450 degrees. Wash and dry produce.

Dice potatoes into ½-inch pieces. Trim and quarter mushrooms (skip if your mushrooms are pre-sliced!). Trim and discard woody bottom ends from asparagus.

In a medium bowl, whisk together cream sauce base, stock concentrate, garlic powder, and 3 TBSP water (6 TBSP for 8).

Place potatoes in a medium pot with enough salted water to cover by 2 inches. Bring to a boil and cook until tender, 15-20 minutes.

Drain and return potatoes to pot; mash with crème fraîche until smooth. Taste and season with salt and pepper. Keep covered off heat until ready to serve.

While potatoes cook, pat chicken* dry with paper towels and season all over with salt and pepper.

Heat a large drizzle of oil in a large pan over medium-high heat. Add chicken and cook until browned and cooked through, 5-7 minutes per side. (For 8 servings, you may need to work in batches.) Remove from heat; transfer to a plate. Wipe out pan.

Melt 2 TBSP butter (4 TBSP for 8 servings) in pan used for chicken over medium-high heat. Add mushrooms and season with salt and pepper. Cook, stirring occasionally, until browned and tender, 3-4 minutes.

Add vinegar and 1 tsp sugar (2 tsp for 8); cook, stirring, until vinegar is mostly reduced, 30-60 seconds.

Transfer mushrooms to an 8-by-8-inch baking dish; top with chicken (for 8 servings, divide mushrooms and chicken between two baking dishes). Pour cream sauce mixture over top to thoroughly coat.

Arrange asparagus in bundles around chicken; sprinkle everything with mozzarella. Season with salt and pepper.

Bake on top rack until asparagus is tender and cheese is melted and lightly browned, 10-12 minutes. (Bake on top and middle racks for 8.)

Serve mashed potatoes and chicken and mushroom bake family style or divide between plates.

Plate it up: Divide mashed potatoes between plates and top with chicken and mushrooms. Top chicken with any remaining sauce from baking dish. Serve with asparagus on the side.