Prepare the homemade buttermilk by mixing milk (room temperature) and white vinegar, mixing, and waiting at least 5 minutes.
Preheat the oven to 350F and prepare two 8” cake pans (brush a little butter and coat with flour; you may also add a round piece of parchment paper on the bottom).
In a medium bowl, whisk the dry ingredients, flour, almond flour, baking soda, baking powder and salt)
Add unsalted butter (ambient temperature), oil, and sugar to the stand mixer bowl with a paddle attachment. Mix on medium speed for about 3 minutes until white and fluffy. You can also use a handheld mixer. Scrape down the sides of the bowl if needed.
Add one egg at a time and mix in between for a few seconds until incorporated.
Add vanilla and ½ cup buttermilk and mix until combined.
Reduce speed to low. Add 1/3 of the flour mixture to the wet ingredients, alternating with the remainder buttermilk until it finishes.
Using a kitchen scale, split the batter evenly between the 2 8” cake pans (about 630 grams each) and bake for about 35 minutes until the cakes are light golden brown and a toothpick comes out clean.
Let the cake layers cool for about 15 minutes. Run a knife around the sides of the pan, then remove them from the baking pan and add them to a cooling rack.