Place a mesh strainer over a bowl and place the fresh grapefruit segments in the strainer. Allow the segments to drain juice into the bowl. Combine ¼ cup (60ml) of the juice and with 1 tbsp. of brown sugar for a syrup. Set aside. (The remaining juice can be used for another recipe.)

Heat your oven to 400°F (204°C). Line the bottom of a 9” (22cm) cake pan with parchment paper, and grease the interior of the pan generously with extra butter (about 1 tbsp./14g)

In the bowl of a food processor, combine the cake flour, chilled butter, 1 tbsp. brown sugar and baking powder. Pulse to combine so that your mixture resembles coarse crumbs. Add the buttermilk and pulse briefly so that the dough gathers into a ball. Avoid over mixing to keep your short cake tender.

Remove the dough from the food processor, and place in the prepared baking pan. Press the dough in the pan to form an evenly thick shortcake. Sprinkle the granulated sugar evenly across the cake surface.

Bake the shortcake for 25 minutes, until a toothpick comes out clean from the center. Allow to cool completely.

Combine the mascarpone or crème fraiche with the brown sugar. Chill until ready to serve.

Decorate the top of your shortcake with the drained grapefruit. Pour over the reserved juice syrup. Serve garnished with the chilled topping.