Begin by melting half of the unsalted butter in a skillet over medium heat. Swirl the pan occasionally until the butter is browned and aromatic, about 5-7 minutes. Remove from heat and allow to cool while preparing the scones.

In a separate mixing bowl, beat the remaining softened unsalted butter until creamy, about 2-3 minutes. Gradually add the cooled brown butter along with light brown sugar, mixing until fully combined and fluffy. Place the icing mixture in the refrigerator for at least 1 hour to firm up.

In a large mixing bowl, whisk together all-purpose flour, white sugar, baking powder, pumpkin spice blend, baking soda, and salt.

Add the cold, cubed unsalted butter into the dry ingredients. Mix until the mixture resembles coarse crumbs.

In another bowl, whisk together pumpkin purée, large egg, buttermilk, apple cider vinegar, and vanilla extract until well blended.

Gently fold the wet mixture into the dry ingredients, ensuring you leave the dough a bit ragged and not overmixed.

Turn the dough out onto a floured surface, being careful not to over-handle. Lightly knead the dough a couple of times and then shape it into a rectangle about 1-inch thick. Cut into squares, then slice diagonally into triangles.

Arrange the shaped scones on a lined baking sheet and place them in the refrigerator to chill for 15-20 minutes.

Preheat your oven to 400°F (200°C). Bake the chilled scones for 12-15 minutes or until golden brown.

Let the baked scones cool on the baking sheet for a few minutes before transferring to a wire rack. Once slightly cooled, drizzle the whipped brown butter icing over each scone.