Instructions

• Preheat the oven to 425 degrees Fahrenheit (218 degrees Celsius). A muffin pan with a capacity of 12 cups should be sprayed with nonstick spray or lined with cupcake liners. There is a possibility that you will require a second pan because this recipe yields up to 14 muffins; however, you can always bake in batches using only one pan. Put aside for later. Please refer to the paragraph regarding the big size and tiny muffins.
• In order to prepare the crumb topping, combine the cinnamon, granulated sugar, and brown sugar in a bowl of medium size. First, include the butter that has been melted, and then use a fork to gently incorporate the flour. Maintain the mixture in the form of large crumbles, and avoid over-mixing it. Should the mixture be over-mixed, it will transform into a thick paste. Put the topping in a separate location.
• Concoct the muffins by:A large basin should be used to combine the flour, baking soda, baking powder, cinnamon, and salt by whisking them together. Put aside for later.
  The butter and both sugars should be mixed together on high speed for approximately two minutes, using a stand mixer or a handheld mixer that is equipped with a paddle attachment. The mixture should be smooth and creamy. When necessary, scrape the sides and bottom of the bowl to remove any residue. To the mixture, add the yogurt, eggs, and vanilla extract. After one minute of beating at a medium speed, increase the speed to high and continue beating until the mixture is completely blended and primarily creamy. (It is acceptable if it has a somewhat curdled appearance.) When necessary, scrape the sides and bottom of the bowl to remove any residue. The dry ingredients and milk should be added to the wet ingredients while the mixer is operating at a low speed. The mixture should be beaten until there are no pockets of flour left. Apples should be folded in.
• Each cup or liner should be filled with the batter until it reaches the top, and the batter should be distributed equally. Spread the crumb topping on each one, and then gently press it down to ensure that it adheres.
• Bake for five minutes at 425 degrees Fahrenheit, and then, while the muffins are still in the oven, lower the temperature to 350 degrees Fahrenheit (177 degrees Celsius). For a further 15–18 minutes, or until a toothpick inserted in the center of the cake comes out clean, continue baking the cake. The cooking time for these muffins in the oven is approximately twenty-three to twenty-four minutes. After allowing the muffins to cool for five minutes in the muffin pan, move them to a wire rack to continue cooling for the remaining five minutes.
• To make the icing, combine all of the ingredients for the icing in a bowl and whisk them together. Drizzle the icing over the muffins while they are still warm or after they have cooled.
• While plain or iced muffins can be stored in the refrigerated for up to a week, they can be kept fresh for a few days if they are covered and kept at room temperature.