Prepare the Crumble Topping: In a medium bowl, combine ¾ cup flour, ¼ cup sugar, ¼ cup brown sugar, and 1 tsp pumpkin pie spice. Add 6 tablespoons of melted unsalted butter and mix with a fork until the mixture forms a crumbly texture. Set aside.
Preheat the Oven: Preheat your oven to 450°F (175°C). Line a 12-cup muffin tin with paper liners or grease it lightly.
Mix the Dry Ingredients: In a large bowl, whisk together 1¾ cups flour, 1 tsp baking soda, 2 tsp ground cinnamon, 1 tsp pumpkin pie spice, and ½ tsp salt.
Combine Wet Ingredients: In another large bowl, mix 1 stick melted butter, ½ cup sugar, and ½ cup brown sugar until smooth. Add 1½ cups pumpkin puree and mix well. Beat in 2 eggs, one at a time, until fully incorporated. Stir in ¼ cup milk until combined.
Combine Wet and Dry Ingredients: Gradually add the dry ingredients to the wet mixture, gently folding until just combined. Do not overmix; the batter should be slightly lumpy. Fold in the optional Nestles Pumpkin Spice Latte Flavor Morsels (8oz Bag)
Fill the Muffin Tin: Divide the batter evenly among the muffin cups, filling each about ¾ full.
Add the Crumble Topping: Sprinkle the prepared crumble topping generously over each muffin, pressing it down lightly so it sticks.
Bake: Bake in the preheated 450 degrees f oven for 5 minutes then reduce the temperature to 350 degrees f for an additional 15-20 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Cool and Serve: Allow the muffins to cool in the tin for about 5 minutes before transferring them to a wire rack to cool completely. Enjoy warm or at room temperature!