Preheat your oven to 425°F and line a large baking sheet with parchment paper.
Slice the russet potato into thin, uniform wedges and toss them in a bowl with 0.5 tablespoons of avocado oil, a pinch of sea salt, and black pepper.
Spread the potato wedges in a single layer on the baking sheet and roast for 15 minutes.
While the potatoes roast, whisk the egg in a shallow bowl and combine the almond flour, garlic powder, onion powder, salt, and pepper in a second shallow bowl.
Pat the cod fillet dry with a paper towel, dip it into the egg wash, and then dredge it through the almond flour mixture until fully coated.
Remove the baking sheet from the oven, move the potatoes to one side, and place the fish on the other side.
Drizzle the remaining avocado oil over the fish and return the tray to the oven for 12 to 15 minutes until the fish is opaque and the potatoes are golden.
Serve the fish and chips immediately with a fresh lemon wedge for a bright, zesty finish.