• Preheat the oven to 350 degrees. Line two muffin tins with paper liners or spray with cooking spray. Set aside.

To make the streusel:

• Combine the flour, brown sugar, cinnamon and salt in a medium bowl. Using a pastry blender, cut the butter into the flour mixture until the mixture looks like coarse crumbs. (If you prefer, you could also combine the dry ingredients and butter in a food processor and pulse to blend.) Stir in the pecans. Set aside.

To make the muffins:

• Whisk together flour, baking soda, salt, cinnamon, and nutmeg in a medium bowl. Set aside.
• In a large bowl, whisk together sugar, oil, water, pumpkin, eggs, and vanilla extract. Whisk until smooth. Slowly fold in the flour mixture. Mix until ingredients are combined. Add ¾ cup of the streusel to the mixture and stir until the streusel is just distributed throughout the batter.
• Divide batter among the muffin cups and top each muffin with remaining streusel. Bake 18 to 20 minutes, or until a toothpick inserted in the center of muffin comes out clean. Allow to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.