Heat the olive oil over medium heat in a large skillet. Add onion and cook until softened.
STEP 2: Add the garlic and cook until fragrant, about 30 seconds, stirring constantly
STEP 3: Add the tomatoes and peppers, stirring and mashing the tomatoes slightly so that they release some of their juices.
STEP 4: Cover and cook over low heat for about 10 minutes.
STEP 5: While the vegetables are cooking, season the haddock on both sides with salt, pepper, and cumin.
STEP 6: Season the vegetables with salt and pepper, add the sage, and stir well. The mixture should look like sauce.
STEP 7: Gently add the haddock to the vegetables, nestling it in the sauce.
STEP 8: Cook, uncovered, over low heat for about 4 minutes, then gently flip the fish and continue cooking until the fish flakes easily, about 3-4 more minutes.
Serve with lemon wedges, if desired, and enjoy!