Preheat the oven to 350F.
Wash, core, and chop the apple into small pieces.
In a bowl whisk together the wet ingredients.
In a separate bowl, mix the apple muffin dry ingredients till there are no clumps.
Gently combine the wet and dry ingredients. Don’t overmix!
Fold the apple pieces into the batter.
In a separate bowl, mix your crumb ingredients. Make sure to soften/ melt your butter first.
Scoop the batter in a lined or greased muffin pan and add the crumble on top. Fill the batter close to the top.
Bake on 350F for 16 – 18 minutes on or until a toothpick comes out clean after inserting in the middle.