Preheat oven to 325°F (160°C). Wrap the outside of a 9-inch springform pan twice with heavy-duty aluminum foil to keep water out during the water bath. Grease the bottom and sides lightly.

In a medium bowl, mix graham cracker crumbs, cocoa (if using), melted butter, and sugar until the mixture resembles wet sand.

Press the crumbs evenly into the bottom (and about 1/2 inch up the sides, if you like) of the prepared springform pan using the bottom of a measuring cup for a firm base. Chill in the fridge while you make the filling.

Beat the room-temperature cream cheese in a large bowl on medium speed until smooth and lump-free (about 2–3 minutes). Scrape the bowl.

Add sugar and beat until combined.

Add eggs one at a time, mixing on low speed and scraping between additions. Don’t overbeat — aim for a silky texture without too much air.

Mix in sour cream, heavy cream, cocoa powder, vanilla, vinegar (or lemon), and a pinch of salt until smooth.

Add gel red food coloring and fold it in gently until the color is even.

Pour the filling over the chilled crust and smooth the top with a spatula.

Place the wrapped springform pan into a large roasting pan. Carefully pour hot (not boiling) water into the roasting pan until it comes halfway up the sides of the springform pan.

Bake at 325°F for 55–70 minutes, or until the edges are set and the center still has a slight wobble.

Turn off the oven and crack the door open. Let the cheesecake sit inside for 1 hour.

Remove from the oven, lift out of the water bath, unwrap foil, and let cool to room temperature on a wire rack.

Refrigerate for at least 6 hours, preferably overnight.

Beat the cream cheese until smooth, add powdered sugar and vanilla, then fold in whipped heavy cream until airy. Spread or pipe over the chilled cheesecake and garnish with crumbs or berries.