In the bowl of a stand mixer fitted with a paddle attachment, cut the butter into small cubes and place in a bowl. Add the flour, sugar, salt and almond flour and beat until the mixture resembles breadcrumbs. Add the egg and bring the mix together until it forms a ball. Roll dough to 1/8-inch thickness between two parchment paper, cover in plastic wrap and refrigerate for 20 minutes. Butter small tart molds and cut dough to fit. Line and trim each mold and freeze for at least 1hours before baking for about 15 minutes until lightly golden.