Pre-heat oven to 400F (200C). Line a cookie sheet with parchment paper.
In a large bowl whisk together the flour, sugar, baking powder and salt.
Add the butter and mascarpone and stir until crumbly.
Add the milk and stir just until combined.
Move to a lightly floured flat surface and gently knead 4-5 times only.
Gently pat the dough to a half inch (1.1 cm) thickness and cut out with a round cookie cutter.
Place the biscuits on a parchment paper lined cookie sheet. Brush with milk and bake for approximately 10 - 12 minutes.
Cool on a wire rack. Enjoy!
Notes
When the biscuits have risen and are a golden brown they should be done.You can always make the dough, cut out the biscuits and freeze, then bake when needed. You can bake them directly from the freezer, although they may need a bit more time to bake.If freezing baked biscuits then make sure they are completely cool, then place them either in a freezer safe bag or container. They will keep for about a month in the freezer.The biscuits should be stored in an air tight container at room temperature. They will keep for up to two days.