Preheat your oven to 400 degrees F. Spray a rimmed baking sheet with oil.
Rinse your cod and feel for any bones to remove. Pat the cod dry with paper towels and place the cod on your baking pan. Wash your hands well.
Melt your butter in a small bowl in the microwave. (Cover your bowl with wax paper to prevent a mess.) Heat the butter for 20 seconds at a time until melted.
Add the lemon juice, garlic powder, pepper and coffee extract to your melted butter and stir it with a spoon or whisk until combined.
Pour the coffee butter over your cod. Bake the cod for 15 minutes, or just until the fish can be easily flaked with a fork.
Add salt to taste and serve immediately. I don't recommend adding extra lemon juice, because it overpowers the coffee flavor. If desired, serve with bread for dipping in the coffee butter from the pan.
The taste and texture are best if the cod is eaten right away, but store any leftovers in the refrigerator for up to three days. Leftovers are best eaten cold.
The recipe as written provides a mild coffee flavor when the fish is cooked. You can experiment with increasing the coffee extract if you're looking for a bolder taste.