# Moist Chocolate Cake

This chocolate cake is deep, dark and truly moist. It mixes in a single bowl with no mixer, and the batter is thin enough to pour.

Hot coffee boosts the chocolate flavor without tasting like coffee. A glossy chocolate ganache turns the two layers into a proper celebration cake that serves 12.

- Total time: 1 h (prep 25 min, cook 35 min)
- Serves: 12
- Per serving (estimated): 420 kcal, 5 g protein
- Cuisine: American. Category: Dessert. Diet: vegetarian.

## Ingredients

- 250 g all-purpose flour (2 cups)
- 300 g granulated sugar (1 1/2 cups)
- 75 g unsweetened cocoa powder (3/4 cup)
- 2 tsp baking soda
- 1 tsp baking powder
- 1 tsp fine salt
- 2 large eggs, room temperature
- 240 ml buttermilk
- 120 ml neutral oil (1/2 cup)
- 2 tsp vanilla extract
- 240 ml hot brewed coffee or hot water
- 225 g semisweet chocolate, chopped, for ganache
- 240 ml heavy cream, for ganache

## Method

1. Heat the oven to 350°F (175°C). Grease two 8-inch (20 cm) round pans, line the bottoms with parchment and dust with cocoa.
2. Whisk 250 g flour, 300 g sugar, 75 g cocoa, baking soda, baking powder and salt in a large bowl.
3. Add the eggs, buttermilk, oil and vanilla. Whisk until smooth.
4. Whisk in the hot coffee. The batter will be very thin, which is correct.
5. Divide the batter between the pans. Tap the pans on the counter to pop big bubbles.
6. Bake 30 to 35 minutes, until a toothpick in the center comes out clean and the cake springs back when pressed. Internal temperature should be about 205°F (96°C).
7. Cool in the pans 10 minutes, then turn out onto a rack and cool completely, about 1 hour.
8. For the ganache, heat 240 ml cream until steaming, not boiling. Pour over 225 g chopped chocolate, wait 3 minutes, then stir until smooth. Cool 30 minutes until spreadable.
9. Spread ganache between the layers and over the top and sides.

## Why it works

- Oil stays liquid at room temperature, so the cake stays moist even when cold from the fridge.
- Hot coffee blooms the cocoa, releasing more flavor, and the thin batter bakes up tender.
- Buttermilk adds acid, which activates the baking soda and softens the crumb.
- Cooling the ganache to a spreadable thickness lets it coat the cake without sliding off.

## The science

- **Why oil makes it moister.** Butter is about 80% fat and the rest water and milk solids, and it firms up when cold. Oil is 100% liquid fat, so the crumb feels soft and moist even straight from the fridge.
- **Why hot liquid in the batter.** Hot coffee dissolves cocoa particles and releases their flavor compounds. It also starts to gelatinize some flour starch, giving a thin batter that bakes into a fine, even crumb. The batter will look too thin, but it bakes up with a fine, even crumb. This is also why the recipe needs no mixer and almost no effort.
- **Ganache ratio.** Equal parts chocolate and cream by weight make a pourable ganache that sets soft. Using 225 g chocolate to 240 ml cream gives a glaze that firms to a spreadable frosting as it cools. Use less cream for a firmer, truffle-like filling. Cooling the ganache at room temperature until it thickens is what makes it spreadable, with no whipping needed.

## Tips

- Line the pans with parchment so the layers release cleanly.
- Level the cooled layers with a serrated knife if they dome.
- Chill the frosted cake 20 minutes for neat slicing.

## Mistakes to avoid

- Opening the oven early can make the middle sink, so wait until at least 28 minutes before checking.
- Spreading ganache while hot makes it run off, so let it cool until it thickens like pudding.
- Overbaking dries out the cake, so stop when a toothpick has no wet batter.

## Variations and swaps

- Use raspberry jam between the layers before the ganache.
- Add 1 tsp instant espresso powder to the batter for a mocha cake.
- Bake the batter in a 9x13 pan for 30 to 35 minutes and glaze the top only.
- Swap buttermilk for 240 ml milk plus 1 tbsp lemon juice, rested 5 minutes.
- Swap hot coffee for hot water if you prefer no coffee flavor.
- Swap Dutch process cocoa for natural cocoa and the cake will be slightly lighter and tangier.

## Storage

Keep the frosted cake covered at room temperature for 2 days, or in the fridge for 5 days. Let slices sit 20 minutes before serving. Freeze unfrosted layers wrapped tightly for up to 2 months.

## FAQ

**Why is my chocolate cake dry?**

It was likely overbaked or the flour was packed too tightly. Weigh the flour and check the cake with a toothpick from 30 minutes. Pull it when no wet batter clings.

**Do I have to use coffee in chocolate cake?**

No. Hot water works fine. Coffee just makes the chocolate flavor taste deeper without making the cake taste like coffee.

**Why is the batter so thin?**

The hot coffee and oil make a very pourable batter. That is normal and gives a moist, tender cake once baked.

**Can I make this in a 9x13 pan?**

Yes. Bake at 350°F (175°C) for 30 to 35 minutes, until a toothpick comes out clean. Cool completely before topping with ganache.

**How do I fix ganache that is too thin?**

Chill it for 15 to 30 minutes, stirring every 10 minutes, until it thickens like pudding. For a lighter frosting, whip the cooled ganache with a whisk for 1 minute.

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Source: https://cookingscientist.com/recipes/chocolate-cake (Cooking Scientist). Learn the science of cooking in the Cooking Scientist app for iPhone and iPad: https://apps.apple.com/app/id6830326846