Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.
In a mixing bowl, whisk together the flour, sugar, baking powder, and salt.
Cut in the cold butter using a pastry cutter or your fingers until the mixture resembles coarse crumbs.
Stir in the chopped walnuts.
In a separate bowl, mix together the maple syrup, heavy cream, and beaten egg.
Pour the wet ingredients into the dry ingredients and stir until just combined.
Turn the dough out onto a floured surface and knead gently a few times. Pat into a circle about 1 inch thick.
Cut the dough into 8 wedges and place them on the prepared baking sheet.
Bake for 18-20 minutes, or until golden brown. Let cool slightly before serving.