Preheat oven to 425 degrees F.
In a smaller bowl, whisk together the flour, pistachio pudding, baking powder and salt.
In a large bowl, whisk together the sugar, eggs, sour cream, oil, milk, 4 tablespoons of melted butter, vanilla and almond extracts until smooth.
Pour the flour mixture into the wet ingredients bowl. Use a rubber spatula to gently stir until combined. Set the bowl of muffin batter aside to rest for a few minutes.
In the third bowl, use a fork to stir together the remaining flour, sugar and brown sugar. Add the remaining melted butter and stir until crumbly.
Use the muffin scoop to evenly fill the muffin liners in the muffin tin. Use a large spoon to evenly sprinkle each muffin with the streusel crumbs.
Bake on the center rack at 425 degrees F for 7 minutes. Don't open the oven door, reduce the oven temperature to 350 degrees F and continue to bake for 3 more minutes. Rotate the pan front to back and continue to bake at 350 degrees F for an additional 12 - 14 minutes, or until a toothpick inserted into the center comes out clean.
Allow the muffins to cool in the pan for 5 minutes. Then carefully remove them to a cooling rack to allow them to finish cooling to room temperature. Keep scrolling for my free printable recipe card and video tutorial.