Thin and Chewy Toffee Bits Cookies

(6 ounces, 12 tablespoons) butter, softened to cool room temperature

granulated sugar

packed light brown sugar

baking soda

salt

vanilla extract

large eggs

all-purpose flour (see note!)

to 2 cups  (8 to 10 ounces) toffee bits (or chocolate covered toffee bits)