Chocolate Sour Cream Cake with Chocolate Frosting

sourcreamchocolatecakecocoa This sour cream chocolate cake is moist, fudgy, completely delicious and so easy to make. It’s the perfect old-fashioned chocolate cake recipe that everyone will love and enjoy at every party. Serve it alone or with ice cream and you’re sure to get rave reviews.

Sour Cream Chocolate Cake:
1¾ cup all-purpose flour, unbleached (250 g)
⅔ cup cocoa powder, such as Dutch cocoa (56 g)
1 tsp. baking powder
1 tsp. baking soda
1 cup granulated sugar (200 g)
½ cup light brown sugar, packed (110 g)
¾ tsp. sea salt
2 large eggs
½ cup vegetable oil, such as sunflower oil (120 mL)
¾ cup full fat sour cream (180 mL)
1 tsp. (5 mL) pure vanilla extract
1 cup hot coffee (240 mL)

Chocolate Frosting:
8 oz dark chocolate, finely chopped (227 g)
¾ cup heavy 35% whipping cream (180 mL)
2 Tbsp. pure honey or corn syrup (30 mL)
2 Tbsp. cocoa powder (12 g)
⅓ cup sour cream (80 mL)

Make the Chocolate Sour Cream Cake:
Preheat oven to 350°F (180°C/160°C fan, Gas Mark 4). Lightly grease and flour two 8" round cake pans and line the base with rounds of parchment paper.

Sift flour, cocoa, baking powder and baking soda into a large bowl. Add both sugars and salt and whisk to blend well, pressing out any lumps of brown sugar.

Combine eggs, oil, sour cream and vanilla in a medium bowl and whisk to blend well. Pour into the bowl with the dry ingredients and mix with an electric hand mixer on medium-low until blended. It will be thick and somewhat dry. Add the hot coffee gradually in two stages to minimize clumps forming and beat until evenly combined and the batter smooth.

Divide batter evenly between the prepared pans and bake for 30-33 minutes until cakes spring back when pressed gently and a skewer inserted into the center comes out clean. Transfer pans to a wire rack and let cool for 15 minutes before inverting onto the rack to cool completely.

While the cakes are cooling, prepare the Chocolate Frosting.

Assemble the Cake:
Once cakes are cooled, place one cake layer on a serving plate. Use an offset spatula to spread about ¾ cup of frosting over the top, spreading it out to the edges. Place the other cake layer on top so it aligns with the sides of the bottom layer. Cover the entire cake with frosting and use the offset spatula to even out the sides and make swooshes and swirls on the top layer.

Make the Chocolate Frosting:
Finely chop the chocolate and place it in a heatproof bowl.

Combine cream and honey or corn syrup in a small 1 qt saucepan over low heat bring it to a gentle boil. Once it reaches a boil, immediately remove it from the heat and pour it over the chopped chocolate. Cover the bowl and let stand for 2 minutes. Then, stir in concentric circles until smooth and glossy.

Sift in cocoa powder, add sour cream and whisk it through gently. Do not beat because incorporating air will cause the ganache to split.

Place the bowl in the fridge for about 20 minutes until thickened. Do not leave it in much longer or it will set up firm. If it is still really runny, then place it back in the fridge for another 5 minutes. Once thick like warm pudding, beat with a whisk until thick and lightened a bit. Stop whisking if it starts to look matte and thick - just whip a few times but it should still stay glossy. It will firm up as you spread it.

Use the frosting immediately. Use and offset spatula to spread it over cooled cake layers right away and avoid spreading around too much which will make it stiffen up.

Note: This recipe makes just enough to cover an 8" round cake with a thin layer to cover the sides because it is very rich. If you prefer a thicker layer of frosting, simple double the quantities of all ingredients and then it will take longer for the mixture to cool until thickened since there is a larger volume.

Makes 10 servings.

Cook's Notes:

If you prefer natural cocoa, my preferences are Ghirardelli 100% Cocoa and Hershey's Unsweetened
What type of oil is best for chocolate cake? Firstly - use a fresh oil. Do not use anything that's been opened for a long time and when you store oil, it should be in a cool dark place. Light and heat accelerate oxidation reactions that can make the flavour turn rancid. My oil of choice for baking is sunflower oil for its clean and neutral taste, but any other oil such as Canola or safflower will do. You can even use olive oil, but keep in mind that it will add the taste of olive oil to the cake.
Which cocoa powder is best for chocolate cake? This recipe works with both Dutch process and natural cocoa powder. For a darker colour like in this photo, I use high fat Dutch cocoa powder. My preference is this one and this one. Natural cocoa has a wonderful fruity flavour and I like to use it as well. You can use Hershey's natural cocoa or this one that I love.
What is a substitute for sour cream? Sour cream really makes this cake delicious, but if sour cream is not available to you where you live, you can also make this recipe using an equal amount of full fat Greek yogurt. I have tested this and it worked well. Another suitable substitution is crème fraîche which is a type of fermented dairy product somewhere between yogurt and sour cream.
How hot does the water/coffee need to be for moist chocolate cake? The coffee or hot water should be very hot. If you brew fresh coffee, then use it immediately when you make the batter. If you use hot water, then bring a kettle to the boil, measure it out and then start making the batter. If it cools for 3-5 minutes, that's fine. If you're making instant coffee, do the same as just mentioned and prepare the coffee fresh off the boil and then start preparing the batter.
Can I make this recipe without coffee? Yes. You can use hot water if you cannot drink caffeine. Or, you can use decaf coffee. You can also make instant coffee instead of brewing a fresh pot, and for this I suggest using 1-2 tsp. of instant coffee for 1 cup of hot water.
What is the secret to super moist cake and how do I make my cake more moist? It's not more fat. Moisture comes from liquid, not fat. So you can add more butter and more oil, but it will really just make the cake more dense and more tender by shortening the texture. Fat will not make a cake moist as only liquids can add moisture. This cake is moist because of the amount of liquid.
How do you add moisture to a chocolate cake? I normally scoff at a cake recipe that uses only oil and no butter since butter is superior for its flavour. However, oil makes the texture very soft and in turn gives the perception of "moistness". That's because oil is made up of mostly unsaturated fats that are liquid at room temperature. Butter contains more saturated fats that are solid at room temperature, therefore the texture of a butter cake will be more crumbly and firm.
Why are my cakes flat? If your cakes baked up flat, it may be that your raising agents are no longer active, so be sure to use fresh baking soda and fresh baking powder. It may also happen if you let the batter sit out for too long before baking. In this case the leavening agents will react in the batter and release gases before the batter sets and the gas will escape through the surface of the batter instead of being trapped as air bubbles in the cake crumb structure.
Can I use this recipe to make cupcakes? Yes you can. It works great. In this case, bake them for 18-20 minutes.
What type of chocolate is best for the best chocolate frosting? Although I mostly use 70% bittersweet chocolate for baking, this frosting recipe is ideal with dark chocolate between 55 and 65% cocoa solids. The sweeter chocolate has less cocoa butter so it won't firm up as quick in the frosting. I prefer this dark chocolate. However, I still often make this with bittersweet chocolate and it is SO delicious, but I just make sure I use it immediately.
What is a substitute for honey? If you can't get a hold of honey, you can replace it with corn syrup or agave syrup. I would not recommend maple syrup since maple syrup contains almost twice as much moisture as honey and it will affect the consistency of the frosting. Honey helps to keep the consistency silky, extra cocoa powder helps to boost the chocolate flavour intensity and sour cream adds a tanginess that complements the sweet and bitter flavours to make for one complex and totally delicious frosting.