Let's make our muffin crumb topping first! To do that, combine all-purpose flour, sugar, cinnamon, and butter in a small glass bowl. Mix well with a fork to make the crumbs. Set aside until ready for use.

Time to make the batter! Start by preheating the oven to 325 F (163 C) in a conventional setting (or otherwise, preheat to 350 F(180 C).

Measure out the dry ingredients and sift them through a sifter and into a large bowl. Combine them together with a wire whisk. Set aside until ready for use.

Next, rinse, peel, and grate apples using a carrot greater. With a chopping knife, chop the grated apple slivers into even smaller pieces.

Then mash the bananas using a fork (or hand mixer) and add to the grated apples. Stir to combine and set aside until ready for use.

Next, beat eggs and sugar in a medium bowl for a few minutes or until fluffy and pale in color. Then add vanilla, apple sauce, and the banana-apple mixture. Mix well to combine.

Stir in the flour using a spatula (or a hand mixer) in 3 separate additions until just incorporated.

Time to bake our delicious muffins! Divide the batter evenly between 12 jumbo or 18 regular liners in a muffin pan. Sprinkle cinnamon crumbs over the top of each muffin batter.

Bake for 20 to 25 minutes or until a toothpick inserted into the center comes out clean.

Remove baked muffins from the oven and let them cool in the pan for 5 minutes before taking them out. Then remove them from the muffin liners and let them cool for an additional 5 minutes. While they are cooling, prepare the cinnamon vanilla glaze.

To make the glaze, combine milk, powdered sugar, cinnamon, and vanilla in a small bowl. Using a hand mixer, beat well. Starting at low speed mix the glaze, gradually increasing the speed as you go.

Drizzle the warm muffins with the delicious glaze. Allow the glaze to dry and stiffen a bit first, and serve warm! Your delicious Apple Cinnamon Muffins are ready to be served!