Preheat the oven to 425°F and line a baking sheet with parchment paper.

In a large bowl, whisk together the flour, sugar, baking powder, and salt.

Cut the cold butter into the dry ingredients using a pastry cutter or your fingers until the mixture resembles coarse crumbs.

In a separate bowl, beat the egg with the heavy cream, vanilla extract, lemon zest, and lemon juice.

Pour the wet ingredients into the dry ingredients and gently stir until just combined, forming a soft dough.

Turn the dough out onto a lightly floured surface, pat into a 1-inch-thick circle, and cut into eight wedges.

Place the wedges on the prepared baking sheet, leaving space between each scone, and bake for 12–15 minutes until golden brown.

While the scones bake, whisk together the powdered sugar and milk to form a smooth glaze; add more milk if needed to reach drizzling consistency.

Remove the scones from the oven, let cool slightly, then drizzle with the lemon glaze before serving.