Line a sheet pan with parchment paper and set aside.
In a large bowl, combine sugar, cinnamon, and both flours.
Add butter and extract.
Blend with fingers to form clumps.
Spread mixture onto sheet pan and bake for 10 minutes.
Remove from oven and move around with an offset spatula. Return to oven for another 5 minutes or until streusel is nice and brown. It will continue to crisp up as it cools.