Preheat the oven to 400℉/200°C. Position rack to middle.
Paper line 18 muffin cups.
Prepare streusel topping (optional) and set it aside. See the instructions below.
In a large mixing bowl, sift together dry ingredients. Whisk in the brown sugar.
Make a well and set it aside for now.
In another bowl, whisk together the egg, oil, applesauce, buttermilk, and vanilla. Set aside.
Grate and chop the apples. Set aside.
Add the wet mixture all at once to the well in the dry ingredients. Stir with a wooden spoon until just moistened.
Gently fold in the apples (grated and chopped).
Fill muffin liners ¾ full. Sprinkle streusel topping over muffin batter (if using).
Bake for 25-30 minutes or until the tops bounce back when lightly touched.
To make streusel topping:
In a small bowl, combine the sugar, flour, oats and cinnamon.
Cut in butter until crumbly.
Set aside (to be sprinkled over muffins prior to baking.
Video
Notes
Whisk the wet and dry ingredients in separate bowls. This prevents the batter from being over-mixed.
Finely chop the apple. This ensures the apples will cook properly and provide a softer texture.
Transfer muffins to a cooling rack once baked. If left in the muffin tins, the bottoms will become soggy.
Can I freeze these muffins? Yes, they can! Can I replace the all-purpose flour with whole wheat flour? Yes, you can replace up to half the amount of all-purpose flour with whole wheat flour and still get great results.Please keep in mind that the nutritional information provided below is just a rough estimate and variations can occur depending on the specific ingredients used.