Caramelised prosciutto tartlets

1.To make pastry, dissolve salt in water. Place 200g butter and 265g flour in a stand mixer with paddle attachment and mix until butter is a pea-sized crumb. Add salted water mixture and continue to mix until dough just comes together. (Alternatively, rub butter into flour with your fingers, add water and stir with a spoon until dough forms.)

2.Turn onto a lightly floured board and knead gently into a smooth ball. Flatten into a disc and wrap well with plastic wrap. Refrigerate overnight. The next day, roll pastry between two sheets of baking paper to 1-2mm thickness. Wrap with plastic wrap and rest for 2hrs.

3.Preheat oven to 190°C (170°C fan). Cut into 24x 8cm-diameter rounds and line tartlet tins. Blind bake, weighted with a tray, for 15mins or until golden and cooked through. Cool in tray on a wire rack.

4.Line a baking tray with baking paper. Sprinkle with half the icing sugar and lay prosciutto on top. Dust with remaining icing sugar, cover with baking paper and weight with a baking tray. Bake until golden and crisp, about 15mins; place on a wire rack. When cool, snap into shards.

5.To make filling, melt remaining 100g butter in a saucepan over medium-low heat. Add onion and bay leaves, season and cook until soft, about 15mins. Add remaining flour and cook a further 3mins, stirring regularly. Add milk gradually and bring to the boil, stirring regularly, to make a thick paste. Stir cheese through and remove from heat. Discard bay leaves and place mixture in a piping bag. Pipe filling into tartlets and top with prosciutto shards. Garnish with sage.