In a fondue pot, combine the chopped chocolate and heavy cream. Heat over low heat, stirring constantly until melted and smooth.

Stir in the vanilla extract and butter until fully incorporated. Keep warm over low heat.

In a saucepan, combine water, sugar, and salt. Bring to a boil.

Remove from heat and stir in flour until a dough forms. Let cool slightly before adding eggs one at a time, mixing until smooth.

Heat oil in a deep pan. Pipe the dough into hot oil, frying until golden brown. Remove and drain on paper towels.

Mix sugar and cinnamon in a bowl and roll the churros in the mixture while still warm.

Serve the warm churros with the chocolate fondue for dipping.