Lavender Butter Cookies

1 cup unsalted butter, room temperature
2/3 cup packed light brown sugar
1 large egg
1 tsp. pure vanilla extract
2 ½ cups sifted all-purpose flour
1 tsp. salt
½ cup turbinado (unrefined) or granulated sugar
lavender to taste

Combine butter and light brown sugar. Beat on high until fluffy, 2-3 minutes. Add egg and vanilla and mix to combine. Add flour and salt and mix on low. Roll out dough into 3 ½ inch logs. Refrigerate until firm, at least 1 hour. Heat oven to 350 degrees. Line sheet with parchment paper and roll cookie log in sugar evenly and slice into 1/4 inch rounds. Bake on cookie sheet 15-20 minutes, until golden brown.