Preheat the oven to 375°F(190°C). Line 12 non-stick standard paper liners into regular size 12 cup-cupcake/muffin pan and set aside.
Place the chopped apples in a small bowl and coat with lemon juice, set aside.
Mix the flour, baking powder, cinnamon, nutmeg, salt in a large bowl. Set aside.
Place the eggs and sugar in a medium bowl and whisk for a minute until combined well. Mix in the melted butter, milk and vanilla extract.
Pour the wet ingredients into dry ingredients and mix until just combined. Gently fold the apples. Don’t overmix the batter so you’ll have light muffins instead of dense ones.
Fill 12 paper liners to the top with the batter. This makes just a little bit more than a large cookie scoop for each cup. Sprinkle the crumbles on top.
Bake for 22-25 minutes or until a toothpick that is inserted into the center of the muffins comes out clean. You don’t want to overbake, so you’ll have moist muffins. Baking time may change from oven to oven so start to check the muffins after 18 minutes. Let the muffins stay in the pan for 10 minutes before transferring on a wire rack to completely cool.