1. Set your temperature to 375°F (190°C). Prepare a jumbo muffin pan by either using cooking spray or placing muffin liners.

Prepare the Muffin Batter:

1. In a mixing bowl cream together 1 ¼ cups of sugar, ½ cup of butter vanilla extract and salt until the mixture becomes fluffy.
2. Add the eggs one at a time. Beat after each addition.
3. In another bowl, combine 1 ¾ cups of flour, 2 tsp of baking powder, and ½ tsp of cinnamon. Mix them together.
4. Gradually add the dry ingredients to the creamed mixture while alternating with adding in ½ cup of milk.
5. Carefully fold in chopped apples (2 cups) and walnuts (about ½ cup).

Prepare the Cinnamon Crumble:

1. In a bowl combine together ¼ cup of sugar, 3 tbsp of flour cubed butter (2 tbsp) and cinnamon (½ tsp) until you achieve a crumbly texture.

Assemble the Muffins:

1. Fill each muffin cup about three-quarters with the batter.
2. Sprinkle the cinnamon crumble on top of each muffin.

Baking Instructions:

1. Place, in the preheated oven. Bake for 30 minutes or until a toothpick inserted comes out clean when tested.
2. If you notice that they are browning quickly on top cover them loosely with foil during the baking process.
3. Once done baking allow them to cool on a wire rack before serving.
4. Enjoy these delicious homemade Jumbo Apple Walnut Muffins!