Combine butter, eggs, sugar, cocoa powder, unsweetened chocolate bar, and 2 cups of chocolate chips into a saucepan over low heat. Continuously stir to avoid chocolate from burning.
OR
Put ingredients into microwave safe bowl and pop into the microwave for 1 minute on high and stir until melted and combined.
After that's mixed, add Kahlua, vanilla and flour until thoroughly combined.
Once batter is cooled, mix in 1 cup of chocolate chips. (Optional)
Lay parchment paper into a small/medium sized pan (I used a 12" x 7 3/4" x 1 3/4") and pour batter into pan. Bake for 50 minutes at 325.
If you're using a larger pan, adjust baking time to avoid burned brownies!
Beat together 1/4 cup Kahlua, butter, cream and sugar until the frosting is thick.
When the brownies are cooled, frost them and serve!