Mix sugar and butter until the mix becomes creamy and white. Add two eggs, one at a time. Add vanilla extract.

Sift together 2 cups of flour, baking powder, salt, and 2 tsp cinnamon powder. Set aside.

Toss diced apples in 2 tsp flour and 1/2 tsp cinnamon powder.

Fold in the flour mix with the sugar mix, alternating with milk. Stir until just combined. Add the sliced apples

Prepare the muffin tray with the cooking spray and coat it with flour. Take the extra flour out after coating.

Scoop the mixture in the prepared muffin tins, filling about 3/4 full. Preheat the oven at 375°F. Bake the muffins for 30 minutes. Check with the toothpick, if it comes out clean.

Mix together the sugar, cinnamon, and melted butter. Pour in on the muffins, once they are ready. Allow them to cool slightly. You can also brush the mixture on the muffins.