Preheat the oven at 350F (180C).
In a small bowl mix the milk and apple cider vinegar. Set aside for a few minutes.
In a large bowl (or the bowl of you stand mixer), stir the flour, sugar, cocoa powder, baking powder and salt.
Add the eggs, milk and apple cider vinegar, oil, melted butter.
Stir until well incorporated.
Poor 3 cups of batter into a 3 silicone cake pan or a buttered regular cake pans.
Bake for 35 minutes. Until a toothpick comes out clean.
Let your cake cool down completely on a grid.
Cut the top of the cakes to make them flat.