Tinned mackerel gratin recipe | Sainsbury`s Magazine

Ingredients

• 1 tbsp olive oil, plus 1 tsp to drizzle
• 1 small onion or large shallot, finely diced
• 1½ tbsp plain flour
• 200ml fish or vegetable stock (made using ½ stock cube)
• 100g sugar snaps
• 1 x 125g tin mackerel fillets in brine, drained and flaked
• 1 x 105g tin Wild Pacific red salmon, drained and flaked
• 1 x 198g tin sweetcorn, drained
• 4 tbsp lighter crème fraîche
• 50g grated lighter mature cheese
• 75g ciabatta, torn into small chunks