PREP: Preheat oven to 425°F. Peel, wash, dry, and cut potatoes into wedges (8 wedges per potato). Grease your sheet pan(s) with cooking spray.
POTATOES: In a large bowl, toss potato wedges with oil & seasonings. I add 1 tsp salt & 1/2 tsp pepper. Space out on sheet pan, cut sides down. Bake 15 min, flip, bake 10 more. Move potatoes to the edges of the pan leaving room in center for fish. Wipe down center with paper towel.
FISH BREADING: Add 2 tbsp oil to large nonstick skillet over medium heat. Add garlic, cook for 30 seconds. Add panko, thyme, salt (1/4 tsp), and toast till golden, 4-6 mins. Remove and transfer to a bowl.
FISH COATING MIXTURES: Prep separate bowls for flour and a whisked mix of egg, Dijon, mayo, salt & pepper (1/4 tsp of each).
PREP FISH: Pat cod dry with paper towel. Cut the cod into equal-sized strips (1/2-inch by 4-1/2 inches).
COAT FISH: Dredge fish pieces in flour, egg mix, then panko. Try to use up all these mixtures. Place on the pan with potatoes, spray everything with cooking spray.
BAKE FISH: Bake 8-13 min until fish is opaque and potatoes are crisp. If needed, remove fish early and finish baking potatoes.
ENJOY: Optionally top fries with Parmesan right out of the oven. Serve immediately with tartar sauce and lemon.
Video
Notes
Note 1: This recipe is perfect on a 15×21 inches sheet pan. For smaller pans, use two to avoid overcrowding and ensure even roasting—one for potatoes, another for fish. If using two pans, place them on the same oven rack.Note 2: Cod is preferred for this dish. If using frozen cod, thaw completely and pat dry before use.Note 3: Tartar sauce is highly recommended for this recipe. It can be made in advance.