Preheat the oven to 350°F and line a baking sheet with parchment paper.
In a medium bowl, whisk together the flour, cornmeal, poppy seeds, baking soda, and salt.
In a stand mixer fitted with the paddle attachment, cream together the butter, sugar, and zests on medium speed until well combined. Add the oil, egg, and lemon juice. Continue mixing until pale and evenly combined, about 1 minute, scraping down the sides as needed.
Add the dry ingredients to the creamed ingredients, mixing on low speed until just combined. The dough will be somewhat dense.
Using a ¼-cup sized cookie scoop, scoop the dough onto the prepared baking sheet (note: these cookies will spread, so leave some room in between each one), and sprinkle the tops with sugar. Bake for 12 to 13 minutes. The cookies will seem like they need a minute longer, but take them out anyways. Let cool on the pan for 1 minute before transferring to a cooling rack to cool completely.
Tip: to bring butter to room temperature more quickly, cut it into skinny shreds, exposing as much of the surface area as possible.
Recipe by Love and Lemons at https://www.loveandlemons.com/lemon-cookies/