Preheat the oven to 325°F. Cover a baking sheet with parchment paper or a silicone baking mat to prevent sticking and promote consistent baking.
Place the almond flour, coconut flour, brown sugar substitute, baking powder, and salt in a large mixing bowl. Whisk until the dry ingredients are evenly distributed.
Fold in the chopped pecans at this stage when using them.
Add the pumpkin purée, eggs, melted butter, and pumpkin pie spice to the dry mixture. Stir just until the ingredients come together and form a unified dough. Avoid excessive mixing to preserve a tender texture.
Transfer the dough to the prepared baking sheet. Gently press it into a rectangle measuring approximately 6 by 8 inches and about 1 inch thick.
Cut the rectangle into six equal squares with a sharp knife. Slice each square diagonally to produce two triangular scones, creating 12 pieces altogether.
Carefully move the shaped scones apart so that none of them are touching.
Bake for 23 minutes, or until the scones feel firm and develop a light golden-brown color. Rotate the baking sheet halfway through the baking period to encourage even browning.
Remove the pan from the oven and allow the scones to cool directly on the baking sheet.
To prepare the glaze, whisk the powdered sugar alternative, heavy whipping cream, and vanilla extract in a small bowl until completely smooth.
Drizzle the vanilla glaze over the cooled scones. Leave the glaze undisturbed for approximately 10 minutes, or until set, before serving.