Place a non-stick or cast iron pan over medium heat for 2 minutes while you slice the red onion thin and soak it in ice water for 7 minutes to remove the harsh bite but keep crunch.
0.5 cup red onion
Pat fresh sardines dry with paper towels, season with salt, then cook 1.5 minutes per side until the flesh turns opaque and flakes easily when pressed gently with a fork. Do not flip more than once to avoid falling apart.
6 pieces fresh sardines, to taste salt
While sardines cook, cut tomatoes into ½-inch wedges and chop fresh parsley or basil finely. Keep herbs separate until the last step to preserve brightness.
2 ripe tomatoes, 2 tbsp fresh parsley or basil
Drain the soaked onion slices, then layer tomatoes and onions in a shallow bowl. Flake the cooked sardines on top and drizzle with 2 tablespoons olive oil and 2 tablespoons lemon juice.
2 ripe tomatoes, 0.5 cup red onion, 6 pieces fresh sardines, 2 tbsp extra virgin olive oil, 2 tbsp lemon juice
Add chopped herbs, season with salt and black pepper, and toss gently once to coat everything without breaking up the sardines. Serve within 10 minutes before tomatoes release too much juice.
2 tbsp fresh parsley or basil, to taste salt, to taste black pepper
