Preheat oven to 350 degrees Fahrenheit (180 degrees Celsius).

In a large mixing bowl, beat margarine and sugar until light and fluffy.

Add eggs, vanilla, baking powder, flour, and dissolved coffee and beat until combined.

On low speed, mix in chocolate and coffee chips until fully incorporated.

Grease two nine-inch (23-centimeter) round pans and divide batter evenly among them. Sprinkle the batter with salt to your liking. (I used about 1/4 teaspoon salt, divided between both pies.)

Place all ingredients for the top layer into the mixer. (No need to wash out the bowl first.) Beat until smooth.

Divide evenly and spread over the bottom layer in the two pans. Sprinkle with walnut nibs, if desired.

Bake for one hour, or until tops are firm (centers will still be a bit soft when tested with a toothpick; this is how you want it!). Remove from oven and set aside to cool.

Serve warm with a scoop of ice cream.