Adjust rack to top position and preheat oven to 425 degrees. Wash and dry all produce. Slice potatoes into 1/3-inch-thick rounds (no need to peel).

Toss potatoes on one side of a baking sheet with a large drizzle of oil, garlic powder, salt, and pepper. Toss carrots on other side of baking sheet with a drizzle of oil, salt, and pepper. Roast until tender and golden brown, about 25 minutes. (For 4 servings, use 2 baking sheets; roast potatoes on top rack and carrots on middle rack.)

While veggies roast, zest and quarter lemon. (For 4 servings, zest 1 lemon; quarter both.) Roughly chop dill, removing any large stems. In a small bowl, combine mayonnaise, sour cream, half the dill, and lemon zest and lemon juice (to taste). Season with salt and pepper.

Once carrots and potatoes have roasted 25 minutes, remove baking sheet from oven and sprinkle potatoes with Parmesan. Return to oven until cheese melts and is lightly browned, 3-5 minutes.

Place panko on a plate. Pat crab cakes dry with paper towels; gently press both sides into panko to coat. Season with salt and pepper. Melt 1 TBSP butter (2 TBSP for 4 servings) in a large pan over medium heat. Working in batches if necessary, add crab cakes and cook until browned and crispy, 4-6 minutes per side.

Toss roasted carrots with a squeeze of lemon juice and a pinch of chili flakes (to taste). Divide between plates along with crab cakes and potatoes. Top crab cakes with lemon dill sauce; serve any extra sauce on the side for dipping. Garnish with remaining dill and serve with any remaining lemon wedges on the side.