Preheat oven to 160°C (140°C fan) mark 3. Grease and line a 25.5cm (10in) round cake tin with baking parchment. Put butter, chocolate and milk into a pan and gently melt until smooth and glossy. Set aside to cool slightly.
Step 2
Meanwhile, sift the flour, baking and cocoa powders into a large bowl, then stir in the sugar. In a separate large jug, mix together eggs and sour cream. Pour both the chocolate and egg mixtures into the flour bowl, and whisk well until combined.
Step 3
Pour cake mixture into the prepared tin and bake in the centre of the oven for about 2hr, or until a skewer inserted into the centre comes out clean. Allow to cool completely in the tin before icing with buttercream and decorating.
Step 4
Finish your cake with White Chocolate Buttercream Filling, and our Chocolate and Fruit Decoration.
Make up to three days ahead. Cool in tin, then take out, wrap in baking parchment, and follow with a layer of aluminium foil. Alternatively, freeze wrapped cake for up to two months. Defrost at cool room temperature, ice and decorate.
An experienced and highly skilled team of food writers, stylists and digital content producers, the Good Housekeeping Cookery Team is a close-knit squad of food obsessives. Cookery Editor Emma Franklin is our resident chilli obsessive and barbecue expert, who spends an inordinate amount of time on holidays poking round the local supermarkets seeking out new and exciting foods. Senior Cookery Writer Alice Shields is a former pastry chef and baking fanatic who loves making bread and would have peanut butter with everything if she could. Her favourite carb is pasta, and our vibrant green spaghetti is her weeknight go-to. Lover of all things savoury, Senior Cookery Writer Grace Evans can be found eating crispy corn and nocellara olives at every opportunity, and will take the cheeseboard over dessert any time (though she cannot resist a slice of tres leches cake). With a wealth of professional kitchen know-how, culinary training and years of experience between them, they are all dedicated to ensuring every Good Housekeeping recipe is the best it can be, so you can trust they’ll work (and if they don’t – we’ll have the answer for why*) every time (*90% of the time the answer is: “buy an separate oven thermometer”!).
