Preheat oven to 350 degrees F. Line a baking sheet with parchment paper; set aside.
In a medium bowl, whisk together the flour, baking soda, and salt.
Using a large mixer on low speed, beat the butter and 1 cup sugar until creamy and light in color, approximately 4 to 5 minutes, scraping down the sides and bottom of the bowl as necessary. Increase speed to medium and add the lemon extract and lemon zest; beat until blended. Reduce speed to low and slowly add the flour mixture until blended. Add the oatmeal and beat until blended.
Using a tablespoon measure, scoop out some cookie dough an roll it between your hands to form a ball (if the dough sticks to your hands, keep a bowl of cold water nearby and occasionally dip your hands in, shaking off the excess water). Place the cookie balls 2 1/2-inch apart on the baking sheet.
Place the reserved 1/3 cup sugar in a small bowl. In another small bowl, fill it with cold water.
Lightly dip the bottom of a flat glass first in the water and then dip the glass in the sugar. Lightly flatten each cookies with the coated glass, refreshing the glass with every couple of cookies.
Bake until the tops are just golden, approximately 12 minutes. Remove from oven and let the cookies cool slightly on the baking sheet before transferring to a rack to completely cool. Repeat with the remaining cookie dough.
Oatmeal Lemon Sugar Cookie Recipe: https://whatscookingamerica.net/cookie/oatmeallemoncookies.htm