To begin, take a medium-sized saucepan and combine the sweetened condensed milk, cocoa powder, unsalted butter, and a pinch of salt. Stir well to dissolve the cocoa into the milk for a smooth consistency.

Place the saucepan over medium heat. Cook the mixture while stirring constantly, making sure it doesn't stick to the bottom of the pan. This is crucial to achieving the thick, fudgy texture characteristic of brigadeiros.

After 10–12 minutes of continuous stirring, the mixture should start pulling away from the sides and bottom of the pan. Test it by tilting the pan slightly, if the mixture slides as a whole mass, it’s ready.

Remove the saucepan from the heat and allow the mixture to cool to room temperature. This step is key to making it firm enough to handle when rolling the truffles.

Once cooled, lightly grease your hands with butter. Take small portions of the chocolate mixture, about the size of a tablespoon, and roll them into smooth, round balls.

Place chocolate sprinkles into a shallow dish. Roll each truffle in the sprinkles, ensuring it's evenly coated on all sides. This is the classic finishing touch for brigadeiros.

Arrange the brigadeiros on a tray lined with parchment paper, ensuring they don't touch each other. You can chill them in the fridge for about 30 minutes to firm up, or serve them immediately if you prefer a softer texture.

Serve the brigadeiros in small paper cups for a traditional presentation. They pair wonderfully with coffee or as a treat after a meal. For an additional garnish, you can top them with sea salt or grated coconut, depending on your taste.