Preheat oven to 400°F (205°C) and line a baking sheet with parchment.
Whisk flour, brown sugar, baking powder, cinnamon, ginger, nutmeg, and salt together.
Add cold cubed butter and cut it into the flour until coarse crumbs form, leaving some pea-sized pieces.
In another bowl, whisk pumpkin puree, egg, maple syrup, 3 tablespoons cream, and vanilla.
Pour the wet mixture into the dry ingredients.
Fold gently until a shaggy dough forms. Add another tablespoon of cold cream only if necessary.
Transfer the dough to a lightly floured surface.
Gently bring it together without kneading.
Pat into a roughly 7-inch disc about 1 inch thick.
Cut into 8 wedges.
Arrange wedges approximately 2 inches apart on the prepared baking sheet.
Refrigerate for 10–15 minutes.
Lightly brush the tops with heavy cream.
Bake for 16–20 minutes until risen, set, and lightly golden around the edges.
Transfer to a wire rack and cool for at least 15 minutes.
Meanwhile, melt 3 tablespoons butter in a small light-colored saucepan over medium-low heat.
Continue cooking, swirling occasionally, until the milk solids become amber-brown and smell nutty.
Immediately transfer the brown butter and browned milk solids to a bowl.
Let cool briefly.
Whisk in powdered sugar, maple syrup, vanilla, salt, and 1 tablespoon milk or cream.
Add additional milk 1 teaspoon at a time until thick but drizzleable.
Drizzle over cooled scones.
Allow the glaze to set for approximately 10 minutes before serving.