Crush lavender using a pestle and mortar. In a medium sized bowl, combine flour, salt, and crushed lavender.
In a large bowl, cream butter and sugar until light and fluffy. Add vanilla extract and milk and continue to beat until combined. Beat in as much of the flour mixture as possible. Add the rest and knead until dough comes together, about 1 to 2 minutes. Wrap in plastic and chill for 15 minutes.
Roll out dough on a lightly floured surface to 1/8 inch (3 mm) thick. Cut into desired shape using a 2½-inch cookie cutter. Add sugar sprinkles before removing cookie cutter. Transfer to a cookie sheet. Repeat until all dough is used up.
Bake cookies in a 375°F (190°C) oven for 8 minutes or until bottoms are very lightly browned. Transfer onto a wire rack and cool completely.