Preheat the oven to 200C/400F/Gas 6.
In a bowl, mix together the butter, flour and sugar, if using. Rub the mixture with your fingertips until it resembles breadcrumbs.
Stir in the grated carrot and roasted butternut squash using a fork.
Bring the mixture together as a dough using your hands, then turn out the dough onto a lightly floured work surface.
Divide the dough into six equally sized pieces. Roll each piece into a sausage shape and place it onto a baking tray.
Flatten the lengths of cookie dough into carrot shapes about 0.5cm/¼in thick, using your hands.
Tear individual mini-sprigs off the rosemary sprigs and insert one into the top of each cookie to resemble the carrot tops.
Bake the cookies in the oven for 15-20 minutes, or until crisp and golden-brown. Remove from the baking tray and set aside to cool on a wire rack.