01 -
Combine flour, cold butter, light brown sugar, granulated sugar, salt, and cinnamon in a small bowl. Use a fork or fingers to cut butter into the mixture until pea-sized clumps form. Stir in diced apples. Refrigerate until needed.
02 -
Preheat oven to 425°F (218°C) and position the rack in the middle. Line 4 muffin cups with liners.
03 -
In a medium bowl, whisk together sour cream, pumpkin, apple juice, granulated sugar, brown sugar, egg yolk, and vanilla until smooth. Fold in diced apples.
04 -
In a separate bowl, whisk together flour, baking soda, salt, and pumpkin pie spice.
05 -
Sprinkle dry mixture over wet ingredients and gently fold with a spatula until no dry streaks remain, taking care not to overmix.
06 -
Divide batter evenly among the muffin liners. Top each with equal portions of the chilled streusel topping.
07 -
Bake at 425°F (218°C) for 5 minutes to achieve lift, then reduce heat to 350°F (177°C) and continue baking for 11 to 13 minutes, or until a toothpick comes out mostly clean.
08 -
Allow muffins to cool in the pan on a wire rack for 10 minutes before transferring to the rack to cool completely.