NOTE: It is SUPER IMPORTANT that all the room temperature ingredients listed above are room temperature and not cold so that the ingredients mix and incorporate correctly.
Preheat your oven to 350º F and prep three 6-inch cake pans (or two 8-inch pans) with cake goop or your preferred pan release.
Add your milk, eggs, yolks, vegetable oil, and vanilla into a small bowl. Give it a quick whisk with a hand whisk and set aside.
Add your flour, sugar, crushed graham crackers, baking soda, baking powder, and salt into the bowl of your stand mixer with the paddle attachment.
Mix your flour mixture for a couple of seconds on low speed to incorporate all the ingredients together.
Add your room temperature butter to your flour mixture. Mix on low speed for 1-2 minutes or until the texture begins to look like coarse sand.
Add ⅓ of your wet ingredients into your flour mixture and mix on medium speed for 2 minutes. Make sure to stop and scrape the bowl in between.
While mixing on low, stream in the rest of your milk mixture and then increase the speed to medium speed and mix until combined.
Divide your batter evenly into your cake pans. PRO TIP: You can use a scale to divide your cake batter evenly between the cake pans for even layers!
Bake the cake layers for about 35-40 minutes or until a toothpick comes out clean from the center. If you are making a larger cake with more batter then the cake will take longer to bake.
Allow your cakes to cool in the pans until the pans are barely warm to the touch before flipping them out onto a cooling rack to cool fully. I like to put my cake layers into the freezer to cool down faster so I can decorate right away. This takes about an hour. You do not need to wrap your cakes in plastic wrap unless you are freezing them overnight.