In a small bowl, combine sugar, flours, nutmeg, and salt. Using a pastry blender, cut in cold butter until mixture is crumbly. Cover and refrigerate for up to 5 days.
Notes
To save time, you can brown the butter and make the Brown Rice Crumb Topping several days before you bake
Recipe by Bake from Scratch at https://staging.bakefromscratch.com/blueberry-browned-butter-buckle/