Homemade Fish Finger Sandwich with Ta Da Sauce  - Another Pantry

Ingredients

• 600g skinless thick white fish fillets – cod, pollack or monkfish
• 75g plain flour
• 1 large egg, beaten with 1 tbsp milk
• 150g fresh white breadcrumbs
• Sunflower oil, for frying
• Salt and pepper
• 1 shallot, roughly chopped
• 1½ tbsp capers, soaked if salted
• 2 tbsp cornichons or pickled cucumbers, chopped
• A handful of parsley/or tarragon leaves (or a mix), roughly chopped
• 100g mayonnaise, shop-bought or homemade
• 100g Greek yogurt
• Juice of ½ lemon