Prepare the Herring:

Drain the matjes herring fillets. For a milder flavor, you may lightly rinse them under cold water. Slice the fillets into bite-sized pieces if desired.

Slice the Onions:

Thinly slice the red onion. To reduce sharpness, soak the slices in cold water for about 10 minutes, then drain.

Prepare the Rolls:

Slice the fresh rolls in half horizontally. Optionally, spread a thin layer of butter or mustard on the cut sides to add richness and flavor.

Assemble the Sandwiches:

Place a few pieces of matjes herring on the bottom half of each roll.

Top with sliced red onions and pickles.

Garnish with fresh dill or parsley if desired.

Squeeze a lemon wedge over the fillings for a fresh, zesty touch.

Serve:

Close the sandwiches with the top halves of the rolls.

Serve immediately, perhaps accompanied by a side of crispy fries or a light salad.