Place the biscuits inside a food processor and pulse till you have small pieces. You want to have visible bigger chunks as they will result in a crispier texture.
Repeat the same procedure for the nuts. Set the biscuits and nuts aside.
On a small nonstick bowl or a microwave safe bowl melt the butter. Pour the melted butter in a big bowl.
Continue by adding the powdered sugar, cocoa powder, vanilla extract and salt and whisk till all ingredients are fully incorporated.
Add the biscuits and nuts in the mixture and give it a good stir.
Let the mixture cool down for 10 to 15 minutes.
Using your hands, form the mixture into small balls and place on a baking sheet with parchment paper. Continue till you have no more mixture left or you can use half and store the rest of it in the freezer for a later time.
Pop the baking sheet in the refrigerator for an hour or so till the truffles are firm.
Before you take the chocolate truffles out of the refrigerator, melt the chocolate. Break the chocolate bar in small pieces and place them in a microwave safe bowl. Microwave on high for 30 seconds, remove the bowl and stir. Repeat the same steps till the chocolate has completely melted and has a velvety texture with no lumps. Let the chocolate to cool down for 2 minutes.
Pour the sprinkles and any other decoration you have chosen into another bowl.
Using two forks, submerge each truffle into the melted chocolate and continue by dipping it into the sprinkles. Add any toppings while the chocolate is still warm.
Place all the decorated chocolate truffles on a baking sheet with parchment paper and let them chill in the refrigerator for another 30 minutes.
Chocolate truffles are ready to enjoy!