I just made these and OMG they are amazing. I didn't add nuts to my topping and I baked them for 25 minutes and they were PERFECT. The only pumpkin muffins I'll be making from now on.
Pumpkin Muffins W/ Struesel Topping | Sweet Hersey Living

Pumpkin Muffins w/ Streusel Topping
•1 1/2 C Flour
•1 tsp. Baking Powder
•1/2 tsp. Baking Soda
•1 tsp. Cinnamon
•1/2 tsp. Ground Ginger
•1/2 tsp. Ground Cloves
•1/4 tsp. Nutmeg
•1 C . Pure Pumpkin Puree
•1 1/4 C. Sugar
•1/3 C. Oil
•2 Eggs

Whisk together dry ingredients, except the sugar, in a medium bowl. In another medium sized bowl whisk together the pumpkin, sugar, oil, and eggs. Gradually whisk the flour mixture into the pumpkin mixture. Do not overmix, once it seems just combined, STOP. Let rest while you make the crumbly topping.

Streusel Topping
•1/2 C. Flour
•1/3 C. Sugar
•1/2 tsp. Cinnamon
•1/4 Chopped Nuts (I didn’t have any this time around. But I’d use either pecans or walnuts)
•3 Tbl. Butter, cut into small pieces

Combine all ingredients in a small bowl with your fingers. Try to work the flour and sugar into the butter. It will eventually all combine and you’ll have a crumble topping!

Spray a 12 cup muffin tin with non stick spray or line with cupcake liners. Pour 1/4 C. muffin mix into each muffin tin. Now top each with a small handful of the streusel topping. Have any leftover? Nope, not ok. Find places to squeeze in every last bit of that topping! You won’t regret it!

Bake at 350 degrees for 20-25 minutes, or until a toothpick inserted in the middle comes out clean. Let cool in muffin tins for 5 minutes before removing to finish cooling on wire rack.