4slicesheirloom tomatosub greenhouse or vine tomatoes in winter
saltI used Maldon sea salt flakes
1tinsmoked mackerel in oilsub smoked salmon or herring
1/2cupbutter lettuce
1tspwhite wine vinegarsub white vinegar or champagne vinegar
Instructions
Spread mayonnaise on each slice of toasted bread. Top 2 pieces of bread with 2 slices of tomato each, then season the tomatoes with a pinch of salt.
Remove mackerel from the tin, reserving the oil. Flake the fish evenly over the tomato. In a bowl, combine 1 tsp of oil from the tin, 1 tsp white wine vinegar, and 1/2 cup butter lettuce. Toss to coat butter lettuce leaves.
Top each sandwich with lettuce and remaining toasted bread. Best enjoyed immediately.