Preheat the oven to 350°F. Have ready an 8x8x2-inch square pan.

To make the bottom layer of the cake, in a small bowl, whisk together the flour, cocoa powder, baking powder and salt.

In a large bowl, combine the butter, light brown sugar and the granulated sugar and whisk to combine. Add the cream and vanilla, whisk again. Add the dry ingredients to the wet, gently whisk to incorporate and transfer the batter to the pan.

To make the top layer, in a small bowl, whisk the light brown sugar, the cocoa powder and the water. Pour this mixture over the batter in the pan, but do not not mix. Bake for about 35 minutes, rotating at the halfway point. The cake is done when it still looks pudding like around the edges, but dryer and more “cake-like” in the middle.

Serve warm with ice cream or a drizzle of heavy cream.