Marble cake

Instructions

1. Step 1

   Preheat the oven to 170°C, grease a 25 cm loaf pan with unsalted butter (to taste), then line the bottom and the two long sides with parchment paper. A well-lined pan keeps the butter cake from sticking and gives it neat, straight sides. The pan is ready when the parchment sticks firmly thanks to the butter.

   Mark step 1 as done

2. Step 2

   Put 225 g softened butter and 225 g granulated sugar in a bowl and beat on medium speed for about four minutes. Beating butter and sugar for a good while traps lots of tiny air bubbles, which helps the cake rise with a fine crumb. The mixture is ready when it's fluffy, pale cream in color and the beaters leave clear trails.

   Suggested time: about 4 minutes.

   Mark step 2 as done

3. Step 3

   Add 200 g beaten eggs to the bowl a little at a time, beating well after each addition, then add 6 g vanilla extract. Room-temperature eggs blend into the butter more easily and won't make the mixture curdle. The mixture is ready when it's creamy and smooth and hasn't split into tiny grains.

   Mark step 3 as done

4. Step 4

   Sift 225 g all-purpose flour with 7 g baking powder and a pinch of salt, add it to the bowl in two additions, alternating with 60 g whole milk, and fold gently. Alternating dry and wet ingredients keeps the batter lump-free without overmixing. The batter is ready when it's thick and smooth and drops from the spatula in soft dollops.

   Mark step 4 as done

5. Step 5

   Spoon about half the batter into another bowl, sift in 25 g cocoa powder, add 30 g whole milk and stir well. The extra milk makes up for the liquid the cocoa absorbs, so both batters end up equally thick. The chocolate batter is ready when it's an even brown and has the same consistency as the vanilla batter.

   Mark step 5 as done

6. Step 6

   Drop alternating spoonfuls of vanilla and chocolate batter into the pan in a checkerboard pattern, building two layers, then plunge a skewer all the way to the bottom and drag it through the length of the pan in an S shape, twice. A few passes keep a clear line between the two colors; too many and they blend into a muddy brown. The batter is ready when you can see distinct two-tone swirls on top.

   Mark step 6 as done

7. Step 7

   Tap the pan gently on the counter and bake at 170°C for about 55 to 60 minutes; if the top browns too quickly, lay a sheet of foil over it. A tall loaf cake needs a long bake for the center to cook through. It's done when the top has a golden brown crack down the middle and a skewer inserted into the center comes out clean.

   Bake at 170°C for about 55 to 60 minutes.

   Mark step 7 as done

8. Step 8

   Leave the cake in the pan for about fifteen minutes, then lift it onto a rack and let it cool completely, about an hour in total. A butter cake needs to cool so its crumb can set; if you slice it hot, the slices will be gummy. It's ready when the slices show crisp swirls and the crumb doesn't stick to the knife.

   Suggested time: about 60 minutes.

   Mark step 8 as done