Preheat oven to 425°F.
Prepare your 8-ounce ramekins by greasing the bottoms and sides with butter or shortening. Then dust with powdered cocoa, making sure all surfaces are covered. Set aside.
Cut up the butter and chocolate into smaller pieces for quicker melting. Melt the butter and chocolate in a double boiler over medium heat, stirring occasionally. Remove from heat when mostly melted and stir until smooth and creamy. **Microwave Instructions: Place the cut-up butter into a medium heat-proof bowl, then add chopped chocolate on top. Microwave on high for 20 seconds, then continue in 10-second increments, stirring after each, until completely melted and smooth. Set aside. Sift the flour, powdered sugar, and instant coffee together into a medium bowl. Set aside.
Whisk the eggs in a separate bowl until pale and foamy. Set aside.
Add the chocolate mixture, the eggs, vanilla, and salt to the flour mixture and whisk slowly until just combined and smooth.
Pour the cake batter into the prepared ramekins, filling almost to the top. Place them on a baking sheet and bake for 10-12 minutes. **Do not overbake! The sides should look done, but the center should still look soft and jiggly. Also, it should look slightly underdone.
Remove the cakes from the oven and let cool for 2 minutes. Then using a kitchen towel or oven mitts, place an inverted plate on top of the ramekin and flip it over. The cake should release easily from the ramekin.
Serve immediately while still warm.
Topping Suggestions: Vanilla ice cream (or other ice cream flavor), chocolate sauce, caramel sauce, raspberries, or strawberries.