Super Easy Tuna Salad Sandwich

1. Combine Greek yoghurt, mustard, mayo, hot sauce, lemon, black pepper, and salt in a large bowl. Mix well and taste, adjusting seasoning as needed.
2. Add the tuna, finely chopped celery stalks, finely chopped red onion, and finely chopped gherkin to the sauce mixture. Stir to combine everything thoroughly.
3. Toast the sourdough bread slices.
4. Divide the tuna salad mixture evenly onto the two slices of toasted sourdough bread.
5. Garnish with finely sliced radishes, fresh herbs, and more black pepper. Serve immediately.

Optional: For a decadent twist, add some grated cheddar on top and bake quickly under the grill until the cheese melts and bubbles.