Step 1

Preheat oven to 400°F/205°C. Line or lightly grease a large baking sheet. Set aside.

Step 2

In a large mixing bowl: whisk together the flour, xanthan gum (if using), baking powder and salt.

Step 3

Add the grated or cubed butter to the flour. Use your hands to rub the butter into the flour mixture until you have a soft, crumbly, lumpy flour.

Step 4

Make a well in the middle of the flour and add the mashed potatoes and milk. Stir until a soft, thick dough forms.

Step 5

Drop large, heaping spoonfuls of the dough onto the prepared baking sheet. Leave a couple of inches in between each biscuit to leave room for growth. Make 6 large biscuits (good for sandwiches) or 8 medium-sized biscuits.

Step 6

Place in the middle of the oven and bake for 25 minutes until puffed and golden in colour.

Step 7

Let cool for a couple of minutes then enjoy warm.