Mix the baking powder in a glass with 4 Tbsp of the milk then add this to 100 g of the flour and mix together until it forms a dough type mixture. Cover with a clean tea towel and set aside until it doubles in size.
Place the rest of the flour (300g) in a bowl and add the eggs, sugar, pinch of salt, the rest of the milk and zest of the lemon. Mix well then add the butter and continue mixing for a further 2 mins then add the dough mixture. Once a smooth dough has been achieved cover and set aside for 2 hours.
After 2 hours knead the mixture a little before placing it on a greased baking tray in the form of a ring. Put some little figures wrapped up in foil inside the mixture and also a broad bean.
Brush with milk, decorate using the mixed peel, lightly sprinkle with sugar and place in a pre-heated oven (160°C/320°F) for 15 - 20 minutes.