Place a saucepan on medium heat and warm the whole milk until it starts steaming but doesn't reach a boil.

While the milk is warming, finely chop the dark chocolate.

In a separate bowl, combine the cocoa powder and sugar.

Once the milk is steaming, take it off the heat and gently stir in the chopped chocolate until it fully melts.

Return the saucepan to low heat and gradually whisk in the cocoa powder mixture until the hot chocolate is silky and well blended.

Add the vanilla extract and stir it in.

Keep the hot chocolate on low heat for a few more minutes, stirring occasionally, until it's hot but not boiling.

Remove it from the heat and carefully pour the hot chocolate into your mugs.

Optionally, you can top each mug with whipped cream or your favourite toppings.

Serve right away and savour your delightful hot chocolate!