1. Preheat oven to 350 degrees F. Spray a 6-cup casserole pan with vegetable cooking spray.
2. In a medium bowl, sift together flour, cocoa powder, baking powder, and salt and set aside.
3. In a large bowl, whisk together eggs, sugar, and butter until smooth. Whisk in milk and vanilla. Add dry ingredients and use a wooden spoon to mix thoroughly, until creamy and smooth.
4. Pour batter into pan and smooth the surface. Sprinkle top with brown sugar. Make the sauce. Combine espresso powder and boiling water, and pour it over batter. It will look watery, but dont worry magic will happen in the oven.
5. Bake at 350 degrees F for 30 to 35 minutes, until cake has risen and is firm to the touch, with sauce bubbling around sides of pan. A toothpick inserted in the center should come out clean. Cool on a wire rack for 5 minutes and serve warm from pan.
Top with whipped cream or ice cream, if desired.
Source: Hannaford fresh Magazine, March - April 2009