2 cups all purpose flour, plus a little extra for dusting 2 tsp salt 170g butter cold, cubed 1 egg beaten 1 large onion, sliced 1 tbs butter 2 tbsp dijon mustard Squeeze of lemon Pinch of salt 700g ripe tomatoes, combination of colours if possible 2 garlic cloves, very thinly sliced 1 cup Grana Padano, plus extra for ganish 2 Tbsp finely sliced chives To serve Fresh rocket
In a bowl, add in the flour salt and butter and work the butter into the flour till almost mixed in, but still with some butter chunks. Add in a splash of water to bring dough together. Form into a disc and allow to rest in the fridge for 1 hour. In a medium heat pan, add in sliced onions and butter with a pinch of salt. Cook slowly covered for about 20 mins – 30 mins till soft and jamy.
Slice tomatoes into ½ slices, cherry or grape tomatoes slice in half lengthways. Mix in a bowl with a pinch of salt and thinly sliced garlic. Preheat the oven to 200c. Roll out dough in between two sheets of baking paper till about 3mm thick. Remove the top layer of baking paper and spread over the dijon mustard leaving a 1.5 inch barrier around the outside of the pastry. Top the mustard with jamy onions, then grate over about a cup of Grana Padano cheese.
Then decoratively arrange your sliced tomatoes and slice garlic, discard any liquid from salty tomatoes. Gently fold over the edges of the pastry to encase the galette. Beat the egg and blush the pastry then the egg wash.