Preheat oven to 350 degrees Fahrenheit. Prepare a 12 cup muffin pan with silicone liners or lightly grease with coconut oil.
Add 1 1/2 cups of oat flour or 1 1/2 cups of oats into a blender and blend into a fine flour. Add baking soda, baking powder, salt, cinnamon, and nutmeg. Blend until fully combined.
Add applesauce, apple cider vinegar, maple syrup, and soy milk. Blend until combined.
Remove blade from blender and stir in 1 3/4 cups of oats until combined. Add sliced almonds and diced apples. Stir until combined.
Scoop muffin mixture evenly into the prepared muffin pan.
Bake in the preheated oven for about 30 minutes, until an inserted toothpick comes out clean. Let cool before eating.