Slice the 10 tablespoons unsalted butter into pieces and melt it in a light-colored skillet over medium heat whisking constantly. Once melted, the butter will begin to foam. Continue whisking for about 5-7 minutes, the butter will become a deep amber color. Remove the browned butter from the heat, and pour it into a bowl. Cover and refrigerate until firm. This should take about four hours. I often brown the butter the night before and refrigerate it overnight.
Add the 3 cups all-purpose flour, ½ cup brown sugar, 1 tablespoon baking powder, 2 teaspoons cinnamon, 1 teaspoon kosher salt, and ½ teaspoon baking soda to the bowl of your food processor.
Cut the chilled browned butter into 4 pieces and added it to the food processor. Pulse a few times to chop and incorporate the butter into the dry ingredients. Continue processing until the butter pieces are the size of peas. Stir in the ½ cup finely chopped pecans.
In a large bowl whisk together the 1 cup heavy whipping cream, 1 large egg, and 1 teaspoon vanilla extract.
Pour the dry ingredients into the wet ingredients and fold them together being careful to not over mix.
Pour the dough onto a lightly floured counter. Knead the dough a few times until it begins to come together and smoothes out a bit. Flatten the dough and fold it into thirds like you would a letter. Give the dough a quarter turn and repeat this flattening and folding process two more times.
Pat into a disc approximately 1 inch thick and cut into eight wedges using a sharp knife.
Transfer the scones to a parchment paper-lined baking sheet. To prevent the scones from spreading chill in the refrigerator for 30 minutes.
Preheat the oven to 425 degrees F.
Brush the scones with heavy cream.
Bake for 14-16 minutes until golden brown.