Preheat oven to 325 Degrees. Line a cookie sheet with parchment paper or a silicone baking sheet. Whisk together the flour, cornmeal and salt and set aside. Cream together the butter and sugar until light and fluffy. Add the egg and vanilla and mix until thoroughly combined. Add the dry ingredients to the butter mixture and mix well. Fold in the lilac blossoms. Using a cookie scoop (I used a heaping teaspoon) drop the cookies about 2 inches apart on prepared baking sheet. Flatten each cookie with a glass dipped in sugar to prevent sticking. Bake in a preheated oven for about 20 minutes or until lightly browned. Cool on wire racks before devouring.