Wash and dry all produce. Adjust rack to upper position and preheat oven to 450 degrees. Lightly oil a baking sheet. Cut sweet potatoes into 1/2-inch-thick wedges.

In a small bowl, mix sour cream, 2 tsp ranch spice (save the rest for the crust), half the lemon juice (1 pack), and a pinch of cayenne (use more to taste). Stir in water 1 tsp at a time until mixture has the consistency of a creamy dressing. Season with salt and pepper.

Microwave 1/2 TBSP butter until melted in another small bowl. Add panko and remaining ranch spice and stir to coat. Set aside. Toss sweet potatoes on one side of baking sheet with a drizzle of oil, salt, and pepper. Place chicken on other side of sheet and season all over with salt and pepper.

Dollop chicken breasts with 1/2 TBSP ranch sauce each. Spread sauce with a spoon to evenly coat top. Press panko mixture into sauce to adhere. Bake in oven until crust is golden, chicken is cooked through, and sweet potatoes begin to brown, about 25 minutes. TIP: If chicken is done before sweet potatoes, remove from baking sheet and set aside.

Meanwhile, peel shallot, then slice into thin rounds. About 10 minutes before chicken is done, melt 1 TBSP butter in a large pan over medium-high heat. Add broccoli and cook, tossing frequently, until bright green and beginning to turn tender, about 4 minutes. (TIP: Add a splash of water to pan to help broccoli cook.) Season with salt and pepper.

Add shallot and another drizzle of oil to pan with broccoli. Cook, tossing, until broccoli and shallot are fully tender, 3-4 minutes. Season with salt and pepper. Divide chicken, broccoli, and sweet potatoes between plates. Add a dollop of remaining ranch sauce to the side for dipping. Sprinkle with lemon juice to taste.