In a medium bowl, cream together the sugar, butter, egg and vanilla.
In a separate bowl, mix together the baking powder and flour.
Add the flour mixture to the sugar mixture alternately with milk.
Mix just until combined. Be careful not to overmix or it may make the cake tough.
In a separate bowl, combine the sugar and cocoa. Add the hot water and vanilla and whisk until combined completely.
Use a store bought single pie crust or your favorite pie crust recipe and press it into a 9" pie plate.
Pour the chocolate mixture into the pie crust, then spoon the cake batter over top the chocolate. Use the back of the spoon to gently spread the batter over top. Be careful doing this and don't worry if it doesn't cover the whole top. It will spread as it bakes. You want the fudgy chocolate to stay on the bottom of the pie and not get mixed in.
Sprinkle the mini chocolate chips over the pie.
Bake for 27-30 minutes until the cake is set.
Serve warm with a scoop of ice cream.
*If you make our pie crust recipe, you can halve it since this recipe only uses a single crust.Refer to the article above for more tips and tricks.The calories shown are based on the pie being cut into 8 pieces, with 1 serving being 1 slice of pie. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information. The information in the nutrition box are calculated through a program and there is room for error. If you need an accurate count, I recommend running the ingredients through your favorite nutrition calculator.**