Grease a baking sheet.
Sift the flour, baking powder and cream of tartar into a food processor, tipping in the grains left in the sieve. Stir in the rosemary and sugar. Add the butter and blend until the mixture resembles breadcrumbs. Stir in the grated carrots and milk and mix to a soft dough, adding a dash more milk if the dough feels dry.
Turn out onto a lightly floured surface and roll out to 1.5 cm (¾ inch) thick. Cut out 22–24 rounds using a 3 cm (1¼ inch) cutter, rerolling the trimmings as necessary. Transfer to the baking sheet and brush with milk to glaze.
Bake in a preheated oven, 220°C (425°F), Gas Mark 7, for 8-10 minutes until risen and pale golden. Transfer to a wire rack to cool.
Split the scones and serve spread with mascarpone and fruit jelly.