Preheat the oven to 350°F and lightly grease or line a muffin tin.
In a small bowl, combine the flax and water. Set aside to thicken. In a measuring cup, combine the almond milk and apple cider vinegar then set aside.
In a large bowl, add the oat flour, almond meal, baking soda, baking powder, cinnamon, ginger and salt. Sift to combine.
In a separate large bowl, combine the pumpkin puree, pure maple syrup, vanilla extract, and almond milk. Add tahini (or coconut oil) last then whisk until thoroughly combined, making sure there are no large lumps. Add the flax and stir a few times.
Add the dry ingredients to the bowl with the wet then use a spatula to fold everything together until just combined. Make sure there are no pockets of flour but be careful not to over-stir. Stir in chocolate chips, nuts or dried fruit.
Fill each muffin tin 3/4 of the way full, sprinkle with brown sugar and ground almonds. Then bake in the oven for 30 minutes, or until a knife comes clean from the center. Allow to cool completely before serving.