Preheat oven to 350 degrees. Gather your ingredients so that you have everything close at hand on the counter or table.
Using a nut chopper, coarsely chop the English walnuts.
Make the Brownie Mix
In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking cocoa, baking powder, and salt.
Add in the whole milk, melted butter, vegetable oil, and vanilla extract. Hand mix with a rubber spatula or wooden spoon to combined.
Pour into a greased square baking pan (or oval baking dish).
Prepare the Pudding Mix
In a small bowl, combine the chopped English walnuts, brown sugar, baking cocoa, and boiling water. Whisk to combine.
Pour over the cake batter. Bake in preheated oven for 35-40 minutes, until set on top. Cake should spring back when touched and will have a creamy chocolate pudding beneath the cake.
Allow to cool on a wire rack. You may serve this cake warm (after about 60 -90 minutes) or cover and refrigerate for 2 or more hours to serve cold.
To serve, scoop spoonfuls of the cake and pudding into small dessert bowls or cups. Serve with a dollop of whipped cream or vanilla ice-cream. Serves 6-8.
Notes
*Unless otherwise indicated, all butter used on this recipe site is salted.