Sautéed shrimp or mussels with vegetable sauce mastiha and feta

Heat 2 tablespoons of olive oil in a large non-stick skillet over medium-high heat and add the chopped spring onions, fennel bulb, chili, and mastiha liqueur. Cover the skillet and cook for 7–10 minutes, until the vegetables soften. If there isn't enough liquid in the skillet, add up to ½ cup of water.
If using shrimp: Heat the remaining 2 tablespoons of olive oil in a large heavy skillet over medium-high heat. Add the shrimp and sauté for about 3 minutes, until they turn a vibrant pink. Transfer the shrimp to the skillet with the vegetables. Add the lemon juice and feta, reduce the heat to medium, cover the skillet, and continue simmering until the cheese is completely melted and the sauce is creamy. Serve immediately.
If using mussels: Add the cleaned mussels to the skillet with the vegetables. Cover the skillet and cook until the mussels open, discarding any that do not open. Add the lemon juice and feta, reduce the heat to medium, and continue simmering until the cheese is fully melted and the sauce becomes creamy, about 4–5 minutes. Serve immediately.