Preheat oven to 425°F and line a baking sheet with parchment paper.
Slice the potato into thin wedges, season with a pinch of salt and pepper, and roast for 25 minutes until crispy.
In a medium bowl, whisk together the spelt flour, baking powder, garlic powder, paprika, and remaining salt and pepper.
Slowly pour the light beer into the flour mixture, whisking until a smooth, bubbly batter forms.
Pat the cod fillets dry with a paper towel to ensure the batter adheres properly to the surface.
Heat the avocado oil in a non-stick skillet over medium-high heat.
Dip each cod fillet into the batter, coating thoroughly, then carefully place in the hot skillet.
Cook the fish for 4 minutes per side until the crust is golden brown and the fish flakes easily.
Serve the hot fish immediately with the roasted potato wedges.