Sour Cream Chocolate Chip Cake with Marshmallow Frosting

This marshmallow frosting is going on everything... everything.

NOTE: You will need an instant-read thermometer for this recipe.

Sour Cream Chocolate Chip Cake with Marshmallow Frosting

slightly adapted from Food Network

For the Cake:
140g unsalted butter
1/2 teaspoon bicarbonate of soda
1/2 teaspoon fine salt
1 1/2 teaspoons baking powder
2 1/2 cups plain flour
2 eggs
1 1/3 cup caster sugar
2 teaspoons vanilla extract
2 cups sour cream
1/4 cup butter milk
1 cup dark chocolate, coarsely chopped

For the Marshmallow Frosting:
5 tablespoons cool water
1/4 teaspoon cream of tartar
1 1/3 cups caster sugar
2 egg whites, room temperature
1 tablespoon light corn syrup
1 teaspoon vanilla extract

Make the Cake:
Preheat the oven to 180 degrees C.

Grease 2 x 20cm round cake pans with cooking oil spray and line the base of each pan with baking paper and put the pans on a baking sheet.

Melt the butter in a small pan over low heat. Remove from the heat and allow to cool slightly. Set aside.

In a medium bowl, sift together the bicarbonate of soda, salt, baking powder and flour.

In a large bowl, beat the eggs, sugar, vanilla and sour cream until smooth. Add the flour mixture in small batched to the wet ingredients and whisk making sure there are no lumps. Pour the melted butter into the batter and whisk until smooth. Fold in the chopped chocolate.

Divide the batter between the cake pans and level the top with a spatula. Bake in the centre of the oven for 40 -45 minutes or until a skewer inserted into the centre of the cakes comes out clean. Let the cakes cool in the pan for 5 minutes then turn them out onto a wire rack to cool completely.

Make the Frosting:
Fill a pan with 4cm water and bring it to the boil. Remove from the heat and set aside.

Combine the water with the cream of tartar, vanilla, sugar and egg whites in a large mixing bowl. Place the bowl over a pan the pan of boiled water. Use and electric hand beater to whip the egg whites over the water. Do not stop beating until this process is finished.

After about 3 minutes, remove the bowl from the heat and take the temperature of the egg whites. You want them to reach 60 degrees C. If the temperature hasn't reached that point, pop the bowl back of the water and keep beating until they do. (Mine took about 7 minutes.) It should look like marshmallow - poufy and shiny. Allow the mixture to cool.

To Assemble:
Put on cake on a cake plate or stand, top it with some frosting, spreading it out to the edges. Top with with another cakes and then dollop the frosting on top and spread evenly over the top and sides of the cake.