To make the madeleines, add the eggs and sugar to a large bowl, and beat well with an electric mixer until it triples its volume and it gets a pale yellow colour.
Add the orange extract and orange zest, and mix again.
Sift the flour, and add it to the mixture together with the baking powder.
Add the butter to a pan set over a low heat, and melt.
Leave to cool slightly, then add it to the bowl too.
Mix well to combine, then cover the bowl with clingfilm, and refrigerate for 20 minutes.
Grease the madeleine pan with butter, then dust with flour.
Chill the pan too.
After the 20 minutes, add a spoonful of batter to each madeleine hole, and bake in the preheated oven at 200 degrees Celsius (390 Fahrenheit) for 10 minutes until golden and firm to touch.
Leave to cool completely.
To make the chocolate dip, break the chocolate into pieces, and add them with the cream to a pan set over a low to medium heat.
Stir well until the chocolate melts, and you get a smooth mixture.
Dip each madeleine into the chocolate, then sprinkle chopped nuts over.
Leave the chocolate to set before serving.