Wash and dry all produce. Adjust rack to upper position and preheat oven to 450 degrees. Strip and finely chop enough rosemary leaves from stems to give you 1 TBSP; save remaining sprigs. Zest lemon until you have 1 tsp zest, then cut into wedges. Pat chicken dry with a paper towel. Season all over with salt and pepper.

Mix together panko, Parmesan, lemon zest, chopped rosemary, and a drizzle of olive oil in a small bowl. Season with salt and pepper. Place chicken smooth side up on a lightly oiled baking sheet. Spread 1 tsp sour cream (we sent more) onto top of one thigh. Repeat with other thighs. Press panko mixture into sour cream to adhere.

Wrap garlic in aluminum foil, sealing to make a pouch. Place on sheet with chicken. Bake in oven until chicken is no longer pink in center and crust is crisp, 20-25 minutes total (we’ll check on it after 10 minutes). Meanwhile, cut potatoes into 1/2-inch cubes. Place in a medium pot with a large pinch of salt and enough water to cover by 1 inch.

Bring potatoes to a boil. Cook until tender, 12-15 minutes. While potatoes cook, halve tomatoes. Once chicken has baked 10 minutes, add tomatoes to same sheet and toss with remaining rosemary sprigs, a drizzle of olive oil, and a pinch of salt and pepper. Continue baking until chicken is done and tomatoes burst, 10-15 minutes.

Once potatoes are tender, reserve 1/4 cup cooking liquid, then drain. Return potatoes to empty pot. Add remaining sour cream, reserved liquid, and 1 TBSP olive oil. Mash until mostly smooth, then season with salt and pepper. Once everything is done roasting in oven, carefully remove garlic from foil and roughly chop. Smash with the back of your knife into a paste. Add garlic to potatoes and mash to combine.

Divide potatoes between plates and top with tomatoes. Add chicken to plate and garnish with rosemary sprigs. Serve with lemon wedges on the side for squeezing over chicken.