Preheat your oven to 325 degrees Fahrenheit. Place 10 unbleached muffin cup paper liners in a standard muffin tin. If you're not using muffin cups, grease the muffin tin with coconut oil or butter.
Grate the apple until you have 1.5 cups. Wrap the shredded apple in cheesecloth (or a clean dish towel) and squeeze out excess liquid. Set aside.
In a small bowl, mix together the crumb topping ingredients and set them aside.
Add the eggs, maple syrup, vanilla, and shredded apple to a food processor and mix until smooth.
Add the almond flour, baking powder, cinnamon salt and mix again.
Divide the muffin batter between ten cups. I use about 2 heaping tablespoons per cup.
Pat the batter down into rounded heaps with lightly oiled hands, then divide the crumb topping between the cups. Pat it down so that it’s smooshed into the batter a little.
Bake the muffins for 30-35 minutes, or until the tops are firm to the touch.