Preheat oven to 350 degrees (F).: When the oven warms up you will notice a faint dry, warm aroma that signals a stable baking environment. This step ensures even rise and browning, so the centers bake through while the edges do not overcook. A common mistake is not allowing the oven to reach temperature, which can cause dense, under risen donuts. If your oven runs hot or cold, use an oven thermometer to confirm the setting.
Lightly grease a doughnut pan; set aside.: Greasing the pan creates a slick surface so the donuts release easily, and you may hear a soft tinking when you tap the pan before pouring batter. Use a pastry brush or nonstick spray to coat each cavity evenly. Too much grease can fry the exterior, while too little will make the donuts stick; aim for a thin, even film.
In a large bowl whisk together the dry ingredients. In a separate bowl whisk together the wet ingredients, then gently pour them into the dry ones. Fold ingredients together until just combined.: As you whisk the dry mix you will see cocoa and flour particles blend into a uniform color, and whisking the wet ingredients creates a glossy, integrated mixture. Folding is gentle work, so stop when streaks remain; over mixing develops gluten and yields a tough crumb. If you overmix, you may notice a gummy texture after baking, so fold briefly and patiently.
Spoon mixture into prepared doughnut pan, and bake for 10-11 minutes, or until the doughnuts spring back when lightly pressed. Be careful not to over bake here!: During baking the batter puffs and the surface firms; you might smell the chocolate intensify and see the edges pull slightly away from the cavities. The spring back test is tactile and reliable, signaling that the interior is set. Leaving them in too long will dry them out, which leads to a crumb that flakes when bit into.
Allow doughnuts to cool a few minutes in the pan before transferring to a doughnut pan to cool completely.: The short rest lets the structure stabilize so the donuts do not break when removed. You will feel a slight give as they cool, and the surface will lose its initial tackiness. Removing them too early may tear the sides, while leaving them in the pan too long could cause condensation on cooling; aim for a gentle window of transfer.
While your doughnuts are cooling, make your ganache!: As you prepare the ganache the aroma shifts to a richer, creamier chocolate scent, and whisking brings a glossy sheen. Making the topping while the donuts cool saves time and ensures the ganache is warm enough to spread smoothly. A pitfall is making the ganache too thin or too thick; adjust with small amounts of cream to reach the ideal spreadable texture.
Sift together the sugar, salt, and cocoa powder. Add cream and whisk until smooth, adding more cream - one tablespoon at a time - if needed to reach a thick but spreadable consistency.: Sifting aerates the dry ingredients and removes lumps, creating a silky ganache when combined with cream. Whisking builds a shiny, uniform mixture, and adding cream slowly helps you control viscosity. If you add too much cream you will end up with a runny glaze, so proceed gradually and stop when the texture coats the back of a spoon.
Using a butter knife spread the ganache generously over the tops of each donut, then top with sprinkles. EAT!: Spreading the ganache should feel smooth and slightly resistant, and the gloss will settle into a thin film as it cools. The sprinkles add a crisp contrast and a cheerful visual pop. A common misstep is applying ganache when donuts are too warm, which can cause the topping to slide off; wait until they are cool to the touch for the best finish.