Mix the dry ingredients in a large bowl; mix the wet ingredients in a medium bowl. Combine the wet and dry mixtures until just mixed together.
Spray a muffin pan with cooking spray and spoon the muffin mixture into the cups. Put the muffins into the preheated oven for about 8 minutes.
While the muffins begin to bake, mix the streusel topping in a small bowl: Measure the sugars and then cut in the butter until crumbs form.
Remove the muffins from the oven and spoon the streusel onto the muffins. Put the muffins back into the oven and continue baking until the muffins are lightly brown and spring back up when touched, about 10-12 more minutes.