Yellow Sheet Cake with Chocolate Frosting
Inspired by techniques from NYT Cooking and America's Test Kitchen.
A big, soft yellow sheet cake baked in one shallow tin and finished with a generous spread of chocolate frosting, cut into squares for easy sharing.
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Method
- 1
Preheat the oven. Heat the oven to 175°C (155°C fan) with a shelf in the middle, giving it at least 20 minutes to reach temperature before baking. Starting hot and steady helps the wide, shallow batter rise evenly across the whole tin rather than doming in the centre.
- 2
Cream butter and sugar. Beat the butter, caster sugar and salt together for 4-5 minutes until pale and noticeably fluffy. This thorough creaming works air into the fat, which is essential for lift in a cake this size.
- 3
Add eggs and vanilla. Beat in the eggs and the extra egg yolk one at a time, mixing well after each addition, then stir in the vanilla. Adding them gradually keeps the mixture from splitting, which would otherwise trap less air.
- 4
Mix in flour and buttermilk. Whisk the flour, baking powder and bicarbonate of soda together, then add to the batter in three additions, alternating with the buttermilk in two, mixing on low until just smooth. The acidity in the buttermilk reacts with the bicarbonate for extra lift and a soft, tender crumb.
- 5
Spread into the tin. Scrape the batter into the tin and spread it evenly, pushing it right into the corners with a spatula. An even layer bakes at a consistent rate, so the edges don't dry out before the centre is done.
- 6
Bake until golden. Bake for 28-34 minutes, until the top is golden, springs back when pressed, and a skewer comes out clean. At this point the proteins in the eggs and flour have set fully, giving the cake a stable crumb.
- 7
Cool completely. Leave the cake to cool completely in the tin on a wire rack before frosting. Frosting a warm cake melts the butter in the icing, so it slides rather than sits in place.
- 8
Make the frosting. Beat the butter for 2 minutes until smooth, then mix in the icing sugar and cocoa powder on low speed. Add the cooled melted chocolate, milk and salt, then beat for 2 minutes until light and fluffy. The melted chocolate deepens the flavour beyond cocoa powder alone.
- 9
Frost and swirl. Spread the frosting evenly over the cooled cake while it's still in the tin, then drag the back of a spoon across the top to create swirls. Cut into 15 squares to serve.
Storage
Store covered at room temperature for up to 3 days, or in the fridge for up to 5 days, bringing it back to room temperature before serving. Unfrosted sponge freezes well for up to 2 months, wrapped tightly.
Equipment
- 23 x 33 cm metal baking tin (not glass), greased and base-lined
- stand mixer or electric hand whisk
- wire rack
- offset palette knife
Nutrition per serving (estimated values)
| Per serving | Amount |
|---|---|
| Energy | 479 kcal |
| Protein | 5.5 g |
| Carbohydrate | 58.1 g |
| of which sugars | 39 g |
| of which free sugars | 37.9 g |
| Fat | 26.3 g |
| of which saturates | 16 g |
| Fibre | 2.5 g |
| Salt | 0.55 g |
Protein per 100 kcal
1.1 g High Protein needs ≥ 10 g
Calculated from USDA FoodData Central ingredient values
