Step 1: Prepare the Apples

1. Peel, core, and dice the apples into small bite-sized pieces.
2. In a bowl, mix the diced apples with the brown sugar and cinnamon. Set aside and allow the apples to macerate, so the flavors meld together.

Step 2: Prepare the Biscuit Dough

1. Preheat your oven to 425°F (220°C). Line a baking sheet with parchment paper.
2. In a large mixing bowl, whisk together the all-purpose flour, baking powder, baking soda, salt, and granulated sugar.
3. Cut the cold butter into small cubes and add it to the flour mixture. Use a pastry cutter or your fingers to blend the butter into the flour until the mixture resembles coarse crumbs.
4. In a separate small bowl, whisk together the buttermilk, egg, and vanilla extract.
5. Gradually pour the wet ingredients into the dry mixture, stirring just until combined. Be careful not to overmix, as this can make the biscuits tough.
6. Gently fold in the cinnamon-sugar apples.

Step 3: Shape the Biscuits

1. Turn the dough out onto a floured surface and gently knead it a few times to bring it together. The dough should be slightly sticky, but manageable.
2. Roll out the dough to about 1/2 inch thick. Use a biscuit cutter (or a round glass) to cut out circles of dough and place them on the prepared baking sheet.
3. Gather any scraps of dough, roll out again, and cut more biscuits.

Step 4: Brush and Bake

1. Brush the tops of the biscuits with melted butter.
2. Bake in the preheated oven for 12-15 minutes or until the biscuits are golden brown on top and cooked through.

Step 5: Prepare the Glaze

1. While the biscuits are baking, whisk together the powdered sugar, milk, and vanilla extract in a small bowl. Adjust the consistency by adding more milk if needed. The glaze should be thick but pourable.

Step 6: Glaze the Biscuits

1. Once the biscuits are out of the oven, allow them to cool slightly on a wire rack.
2. Drizzle the glaze generously over the top of each biscuit.

Cooking Note: