Read through this recipe carefully. Make certain ingredients are at room temperture where noted. Preheat oven to 350 degrees. Butter and flour the sides and base of two 9″ round cake pans. Set aside.
In the bowl of a stand mixer, cream sugar and butter until yellow and fluffy. Add eggs, one at a time until incorporated.
In another bowl, sift flour, baking powder and poppy seeds. Slowly begin to add the flour mixture on low speed into the bowl of the mixer. Do not over beat. On low speed, add in lemon juice, lemon zest, buttermilk and vanilla.
Divide the batter in half and pour into prepared pans. Bake for 20-25 minutes. Check with a cake tester for doneness. Remove from oven and let cool on a wire rack to room temperature. Once cooled, loosen with a sharp knife from edges of the pans and let rest until ready for frosting. You can wrap in plastic and freeze until needed.