Put roughly 2 tablespoons of butter to melt in the pot.
Set the stove top to medium-low.
Once the butter is melted, add a whole can of condensed milk.
If using cocoa powder, dissolve it in a bit of water before adding to the condensed milk.
Stir with the wooden spoon for at least 20 minutes, up to 40 minutes, stirring in circular movements.
The Brigadeiro is ready when it holds its shape when divided with a spoon and when it stays on the spoon for a moment before falling back.
Spread the mixture on a plate and refrigerate for about 30 minutes.
Spread a little butter on your hands, scoop some Brigadeiro, and roll it into a ball.
Roll the ball in chocolate sprinkles to cover it completely.
Place the brigadeiro in a baking cup.
Repeat until all mixture is used, yielding about 25 brigadeiros.
Refrigerate for another 15-30 minutes to firm up.
