Chocolate Cake Recipe Critique

I am in the process of developing my own chocolate cake recipe. I just recently did so for chocolate chip cookies and it was a complete success so I figured I would try again for my 2nd favourite dessert (who am I kidding, you can't just pick one favourite). I am looking for any sort of critiques on my recipe (that I have NOT made yet) to allow me to test a few renditions of it as possible, as ingredients are expensive. Such as if I have missed anything, if proportions are off, or if the recipe will flat-out not work (not enough leavening, etc). Without further ado, here is [hopefully] Moist Chocolate Cake V1.0

100g/4oz chocolate (60%+)

3/4 cup cocoa powder

1/2 cup freshly brewed coffee

3/4 cup butter

3/4 cup brown sugar

3/4 cup white sugar

3 eggs

1 tbsp vanilla extract

1 cup sour cream/buttermilk/Greek yogurt/creme fraiche/another acidic dairy product you might recommend

2 1/2 cups cake flour (Might change to all purpose, as I like a denser cake)

2 tsp baking powder

1 tsp baking soda

1/4 tsp salt

1. Melt the first 4 ingredients together over double boiler
2. Combine the last 4 ingredients together (whisk/sift)
3. Whisk the sugars, eggs, and vanilla together.
4. Combine the cooled chocolate mixture with the egg mixture
5. Add in the dry ingredients, alternating with the dairy in 2 or 3 additions each.

I've also contemplated changing step 3 a bit. Whisking the brown sugar, half the white sugar, egg yolks, and vanilla together while saving the other half of the sugar to beat with the egg whites to create a meringue to help leaven the cake. That being said, all input is valued and greatly appreciated!

bon appetit