Mix yogurt with sugar, add flour, baking powder, mix, add milk, vanilla extract, mix, add melted margarine, mix well until smooth.
Leave to rest for at least 12 hours in the refrigerator.
Preheat the oven to 220°C. Oil and flour the molds.
Pour a little mixture into the molds, up to about 3/4.
Bake for 6 to 8 minutes, until the bump forms, then reduce to 180°C until golden, another 5 to 7 minutes.
Heat the chocolate in a saucepan with the vegetable milk, and dip the madeleines in it!