Put the cubed butter in the freezer for 5-10 minutes.
In a large mixing bowl, whisk together the flour, salt, sugar, bicarbonate of soda and baking powder. Add the cubes of cold butter and, using a pastry cutter, cut the butter into the dry ingredients and toss until the flour coats the butter and the mixture forms chickpea- sized pieces.
Using your hands, make a well in the centre of the mixture. Add the cold buttermilk and cream to the well and toss with your hands until just combined. Fold in the grated cheddar and jalapeño until just incorporated, taking care not to overmix.
Set the dough on a lightly floured work surface and use your hands to gather it into a rough ball. If it feels too dry, add up to 1tbsp more buttermilk. Using your hands, press the dough into a 2.5cm-thick rectangle. Using a sharp knife, cut it into quarters and stack them on top of one another. Press the dough into a 10x15cm rectangle, wrap with cling film and transfer to the freezer to chill for 10 minutes.
Preheat the oven to 220C/200C F/Gas 7. Line a baking sheet with baking paper. Beat together all the ingredients for the egg wash.
Set the dough on the work surface and roll it out to a 15x23cm rectangle. Using a 6-7.5cm round cookie cutter or upside-down glass, cut out six biscuits. Gather the scraps and press together to cut two more biscuits. Alternatively, use a sharp knife to cut the dough into six rectangular pieces. Transfer the biscuits to the prepared baking sheet and brush the egg wash over.
Bake for 14-17 minutes until golden brown and transfer to a cooling rack. Brush the butter and honey, if using, over the top of the biscuits and serve warm.
Recipes and photographs taken from Turkuaz Kitchen by Betül Tunç, photography by Betül Tunç (Square Peg, £25)
