Melt the dark chocolate either in a microwave or on stove top using double boiler till it is fully melted.
Mix condensed milk to the melted chocolate till completely incorporated.
Add peanut butter to the chocolate-condensed milk and mix well.
Now pour this into a flat container lined with aluminium foil. Flatten the mix and refrigerate to cool down and set.
After setting, bring out the chocolate peanut butter fudge and cut into squares. Keep refrigerated in the fridge. Consume as needed.
If using a microwave to melt the chocolate, cut your bar into smaller pieces. Run the microwave 1-2 minutes at a time and then mix well with a spatula.
If using a stove top, heat some water in a pan. Now take chocolate in another pan that can be put on top of this pan with boiling water. Let the steam from the boiling water help in melting the chocolate. Never directly heat the chocolate. It may burn.
If not using chunky peanut butter, you can add nuts like walnuts, almonds, cashews or even roasted peanuts etc.
You can make two separate layers -- one of chocolate-condensed milk and another of peanut butter if you so like. This you can do when pouring the mix in the foil.
This delicious fudge is a perfect dessert treat, not too high on calories and really a favourite of everyone who likes chocolate.