Preheat oven to 350°F
Make sure eggs and butter are at room tempurature before beginning
Measure out ½ cup of whole milk and add 6 tablespoons of vegetable oil to it. Set aside.
Measure out ¾ cups of whole milk and add the eggs to it along with 1 teaspoon of vanilla. Give it a whisk and set it aside
In the bowl of a stand mixer or KitchenAid, add the cake flour, salt, baking soda, baking powder, and 1 ¾ cups of the granulated sugar.
Begin mixing on the lowest speed. Cut up the softened butter into 2 tablespoon chunks and begin adding one at a time to the mixing bowl on low speed. This process should take a few minutes, and when it is all incorporated it will look like coarse sand.
After the butter is incorporated, add the milk and oil mixture. Turn the mixer onto medium speed (about 3-4 in a KitchenAid) and let it mix for 2 minutes. This process is called reverse creaming.
After the 2 minutes is done, it should be very fluffy, now add the milk and eggs mixture, along with the lemon zest and lemon juice. Mix on low until it is just incorporated. Scrape down the sides and give it one more mix.
Pour the lemon butter cake batter into 2 prepared 8" cake pans.
Evenly top each cake with 1 ½ cups of frozen berries then top each cake with half of the lemon streusel topping.
Bake in a preheated oven for about 30 minutes. Toothpick should come out clear one inch from the edge. Don't overbake!