Preheat oven to 325 degrees. In a large bowl, combine oil, eggs, milk, lemon juice, and zest; cream for 2 minutes. Separately, stir together sugar, flour, baking powder, baking soda, and salt, then fold into the wet mixture.

Generously spray two 9-inch or three 8-inch cake pans with nonstick cooking spray.

Divide batter into prepared pans. Bake 8-inch pans for 20-26 minutes, or 9-inch pans for 30-36 minutes, until a toothpick comes out clean. Cool completely.

For the frosting, cream softened butter and cream cheese in a large bowl for 4-5 minutes until light and fluffy. Add powdered sugar, lemon juice, vanilla, and lemon zest, then cream until combined. Chill the frosting.

To assemble, place one cooled cake layer on a plate. Spread lemon curd on top, followed by a layer of frosting. Repeat with the subsequent cake layers, spreading lemon curd and frosting, then frost the entire cake.

Chill the assembled cake for 20-30 minutes to allow the frosting to set. Store any leftover cake covered in the refrigerator.