Chocolate Cake

Method

1. prep6 min
   oven to 350°F / 175°C
   grease and line a single 6-inch round pan or six cupcake cups — this batter is engineered for one thin layer, and a taller pan is the one change that ruins it
2. whisk2 min
   dry, sifted
   flour + sifted cocoa powder + sugar + baking soda + baking powder + salt — cocoa must go through a sieve, because its fat content makes it clump and a dry clump will not dissolve later; it bakes as a bitter grey speck
3. whisk2 min
   room temperature
   egg + buttermilk + oil + vanilla in a second bowl until uniform — cold buttermilk will seize the oil into beads that never disperse, so let it sit out first
4. fold2 min
   by hand, barely combined
   wet into dry, stopping while streaks of flour still show — this is a liquid batter with no creamed air to protect it, so any gluten you develop with a mixer shows up as rubbery tunnels
5. mix2 min
   liquid boiling hot
   + boiling coffee poured in a thin stream, stirred just to smooth. The heat blooms the cocoa — it melts the cocoa butter and dissolves the solids so the flavour reads as chocolate rather than dust. The batter will now be as thin as cream. That is correct; do not add flour to thicken it
6. bake30 min
   350°F / 175°C, center rack
   pour and bake until the top springs back and a skewer comes out with two or three moist crumbs clinging. A clean skewer means you are already past it: carryover heat keeps setting the crumb for several minutes out of the oven, and an oil cake gives you no buttery cover for dryness
7. rest40 min
   10 minutes in pan, then on a rack
   turn out and cool to fully room temperature. Frosting a warm cake melts the ganache off the sides and steams the crumb into a gummy skin — this wait is not optional patience, it is the difference between glaze and puddle
8. emulsify6 min
   cream just steaming, not boiled
   heat the cream until it shivers at the edges, pour it over the chocolate chips, and leave it undisturbed 2 minutes before whisking from the center outward. Stirring immediately drops the temperature unevenly and the cocoa butter separates out grainy; the still minute lets the chocolate melt through so the whisk only has to bring fat and water together = ganache
9. mix3 min
   off heat, cooled to spreadable
   + softened butter whisked in for gloss and a softer set, then let the ganache thicken to the body of mayonnaise before it goes anywhere near the cake
10. top2 min
    cake fully cool
    spread the ganache over the top and down the sides, swirling with the back of the spoon; finish with flaky salt if using, which sharpens the cocoa's bitterness into something that reads as darker chocolate