Preheat oven to 350°F. Line three 8-inch cake pans with parchment paper and spray with nonstick spray.
In a large bowl, whisk together flour, baking powder, baking soda, ground rosemary, salt, and granulated sugar.
Add the eggs, oil, lemon extract, lemon zest, lemon juice, and milk. Mix on medium speed with an electric mixer until all ingredients are incorporated, 1 to 2 minutes.
Divide batter evenly among cake pans. Bake for 23-25 minutes or until cakes are golden brown and set in the center. (Test by inserting a toothpick into the center of each cake layer. If it comes out clean, they're done!)
Let cakes cool in pans for about 10 minutes before transferring to a wire rack to cool completely.