Preheat the oven to 400°F (200°C) and line a baking sheet with a silicone baking mat.
Combine the flour, sugar, baking powder, cinnamon, and salt in the bowl of a stand mixer.
Add the butter and mix on low speed until the butter is in pea-sized pieces.
Whisk together the heavy cream and vanilla. Add to the flour mixture and mix on low speed just until a shaggy dough forms and no dry flour remains. If needed, add additional heavy cream, 1 tablespoon at a time, until the dough holds together when gently pressed.
Turn the dough onto a lightly floured surface and gently pat it into a ¾-inch thick circle. Cut into 8 equal wedges.
Transfer the wedges to the prepared baking sheet, leaving space between them.
Whisk together the heavy cream, sugar, and cinnamon for the topping. Brush generously over the tops of the scones.
Bake for 18–20 minutes, or until golden brown and baked through. Transfer the scones to a wire rack and cool until just slightly warm.
Whisk together the powdered sugar, heavy cream, and vanilla for the glaze until smooth, adding a few drops of heavy cream if needed for a drizzling consistency. Drizzle over the scones and serve.
Notes
Keep the butter cold until you're ready to mix the dough. Cold butter creates tender scones with a light texture.
Let the scones cool until just slightly warm before glazing so the glaze sets on top instead of slipping off the scones.
Store leftover scones in an airtight container at room temperature for up to 2 days or refrigerate for up to 5 days. Warm briefly before serving, if desired.
Freeze unglazed scones for up to 3 months. Thaw at room temperature, warm lightly, and glaze just before serving for the best texture and appearance.