Preheat your oven to 300-F and line a baking sheet with parchment paper.
Whisk together the all-purpose flour and baking soda in a medium bowl. Stir in the lemon zest and poppy seeds.
Cream the salted butter and white sugar in the bowl of your stand mixer with the paddle attachment or with a hand mixer until light and fluffy. This should take about 3-4 minutes.
Add the egg yolks and whole egg, one at a time, to the butter and sugar mixture, beating well after each addition. Then, mix in the lemon oil or extract.
Combine the dry ingredients with the wet ingredients, mixing until just incorporated. Be careful not to overmix.
Scoop the dough by rounded tablespoonfuls (I use a 1.5 tablespoon cookie scoop) onto the prepared baking sheet, leaving about 2 inches between each cookie.
Bake for about 22 minutes or until the edges are lightly golden. Let the cookies cool on the baking sheet for a few minutes before transferring to a wire rack to cool completely.
Notes
Chef Jenn's Recipe Notes
Use fresh lemon zest for the best flavor. The oils in the zest add a bright, citrusy punch that can't be beaten.
If you're not a fan of lemon oil, lemon extract is a fine substitute, but keep in mind that oils tend to have a more potent flavor. You’ll need about 2 teaspoons of lemon extract if you’re not using lemon oil.
For evenly sized cookies, use a cookie scoop or a tablespoon to measure out the dough.