Combine fl our, brown sugar, and salt on low speed of mixer using fl at beater. If necessary, hold parchment paper over bowl opening during mixing, to prevent loss of streusel from bowl. Cut butter...

Combine fl our, brown sugar, and salt on low speed of mixer using fl at beater. If necessary, hold parchment paper over bowl opening during mixing, to prevent loss of streusel from bowl.

Cut butter into chunks and add to fl our mixture. Stir on low speed for 2 minutes or until well-blended and crumbly.