No-Bun Burger

Ingredients

• 2 shallots, finely diced
• 2 large gherkins, finely diced
• 4 tomatoes, skinned, deseeded and finely diced
• 3/4 ounce chives, finely chopped
• 1 small chili, finely chopped
• 3 tablespoons wholegrain mustard
• juice of 1/2 lime
• 1 tomato, diced
• 1 teaspoon honey
• 12 ounces finely minced feather or onglet steak
• Salt and freshly ground black pepper
• olive oil, for frying
• 4 portobello mushrooms, trimmed
• little gem heart leaves
• beef tomato, sliced
• red onion, sliced
• 1 large gherkin, halved lengthways