Fish Ceviche

Instructions

1. Prepare the fish
   Ensure the fish is very fresh and of high quality. Cut it into 1/2-inch cubes, removing any skin or bones. Place in a glass or ceramic bowl (avoid metal as it can react with citrus).
2. Marinate the fish
   Pour the lime and lemon juice over the fish, ensuring all pieces are completely submerged. Cover and refrigerate for 20-30 minutes, or until the fish becomes opaque and appears 'cooked' by the acid.
3. Prepare the vegetables
   While the fish is marinating, thinly slice the red onion, dice the tomatoes after removing seeds, finely chop the jalapeño or serrano peppers (remove seeds for less heat), dice the cucumber, and roughly chop the cilantro.
4. Combine ingredients
   Once the fish has turned opaque, drain about half of the citrus juice. Add the sliced onion, diced tomatoes, jalapeños, cucumber, and half of the cilantro to the bowl with the fish. Gently mix everything together.
5. Season the ceviche
   Add salt, freshly ground black pepper, and olive oil to the mixture. Stir gently to combine, being careful not to break up the fish pieces. Adjust seasoning to taste.
6. Final touches
   Just before serving, fold in the diced avocado and the remaining cilantro. The avocado is added last to prevent it from becoming mushy during marination.