In a bowl, mix together the oat flour, wholewheat flour, salt, and baking powder.
Add the butter and honey.
Use a fork or pastry cutter to incorporate them until the mixture resembles fine breadcrumbs.
Pour in the milk and gently mix until a soft, slightly moist dough forms. Cover and let the dough rest in the fridge for about 15 minutes.
Preheat your oven to 350°F (180°C) and line a baking sheet with parchment paper.
Lightly flour your work surface.
Roll out the dough to about ⅛ inch (3mm) thickness.
Cut out circles about 3-inch (7-8cm) in diameter, gathering and re-rolling any scraps as needed.
Place the biscuits onto the prepared baking sheet, leaving a little space between them.
Prick the biscuits with a fork.
Bake for 15–18 minutes, or until lightly golden.
Let the biscuits cool completely on a wire rack before storing them in an airtight container.
They’ll keep well for 3–4 days.