Apple, hazelnut and rosemary galette with brown butter pastry

Method

1. Cook the butter in a saucepan over a medium heat until the white solids turn a deep amber brown, it begins to smell nutty and stops making a loud sizzling sound. Season with the salt, then transfer to a container and put in the fridge (or freezer) until solidified again.
2. Once the butter has set, dice it into cubes, then add to a food processor with the flour and whizz until you have a sandy texture. Add 1 of the eggs and pulse until it comes together as a dough, adding a splash of cold water if needed. Tip out onto a clean work surface and bring together into a clump of dough, then divide into 2 balls, being careful not to overwork the pastry. Flatten the balls slightly, then cover and rest in the fridge for an hour.
3. Heat the oven to 180ºC fan/gas 6 with a large baking sheet inside to heat up. Mix the ground hazelnuts, sugar and cinnamon in a bowl. Halve, core and slice the apples into 2-3mm thick slices and put them in a second bowl with the lemon juice and rosemary.
4. Roll the pastry balls out into ovals or circles around 3mm thick on sheets of baking paper. Scatter the hazelnut mixture onto each, leaving a 2cm border around the outside, then arrange the apple slices in neat rows. Fold the pastry border back in on itself to create a rustic galette, making little pleats as you go, then beat the remaining egg and brush the exposed border with it. Bake in the oven for 20-25 minutes, then brush with the maple syrup and serve warm or cold.