Melt the butter in a non-stick saucepan, whisk in the condensed milk and cocoa powder, keep whisking till smooth.
Add salt and vanilla.
Cook over medium-low to medium heat STIRRING CONSTANLY until the mixture thickens and starts to peel away or show the bottom of the pan when you scrape it with your wood spoon (about 5-8 minutes).
When you run a spoon through the bottom the pan should show for a few seconds before settling back in on itself.
Let cool to room temperature before starting to roll them into 1 tbsp sized balls with greased hands or a greased cookie scoop (my instrument of choice). Please use a baking measure tablespoon and not a serving spoon for reference!
Roll the fudge balls in the chocolate vermicellis until totally covered
Store for a day, two at absolute most tightly covered.
Measurements for a 300ml can of condensed milk: 3tbsp cocoa powder, 300 ml condensed milk, 1 tbsp butter, ½ cup sprinkles, ⅛ tsp salt.