Step 1

1 Make the cake: Position a rack in the middle of the oven and preheat to 350 degrees

Step 2

2 Grease the bottom and sides of an 8-inch square (or 9-inch round) baking pan and line the pan with a piece of parchment paper so there is generous overhang on both sides

Step 3

3 (If using a 9-inch round cake pan, you may need to trim the parchment width to fit inside the pan, but still be sure to have generous overhang on both sides

Step 4

4 )

Step 5

5 In a large bowl, whisk the brown sugar and eggs until pale and foamy, about 2 minutes

Step 6

6 Add the yogurt, oil, vanilla and salt and whisk until smooth

Step 7

7 Using a fine-mesh sieve, sift the cocoa powder over the mixture and whisk until no lumps remain

Step 8

8 Add the flour, baking powder and baking soda and whisk just until smooth

Step 9

9 Fold in the chopped chocolate or chocolate chips, if using

Step 10

10 Pour the batter into the prepared pan, tap the pan gently on the counter to release any air bubbles, and smooth the top of the batter with a spatula

Step 11

11 Bake for 35 to 45 minutes, or until the cake is puffed and a cake tester or skewer inserted into the center comes out clean

Step 12

12 Transfer the cake to a wire rack and let cool for about 15 minutes

Step 13

13 Then, use the parchment overhang to lift the cake out and let cool completely on the rack

Step 14

14 Make the glaze and finish the cake: Once the cake is completely cool, in a medium bowl, whisk together the confectioners’ sugar, milk, vanilla and salt until smooth

Step 15

15 Add more milk, 1 teaspoon at a time, to make a thick but pourable glaze

Step 16

16 Immediately pour the glaze over the cooled cake (the glaze will start to harden if you let it sit)

Step 17

17 Decorate with sprinkles, chopped nuts or a drizzle of melted chocolate, if desired

Step 18

18 Let the glaze set for about 15 minutes before slicing the cake