1. In a big bowl, combine the flour, sugar, and yeast. To form a thick, sticky batter, whisk the salt, milk, and eggs together in a jug before adding them to the flour mixture and beating well with a wooden spoon for about five minutes.
2. Add the butter gradually while beating the mixture until it is glossy, elastic, and smooth. The zest of the orange and lemon is then added. The dish should be covered with cling film and given an hour to rise.
3. Pour the sugar into a pan, add the lemon juice and 150 ml (5 fl oz) of water, and stir until the sugar dissolves to make the syrup. Add the orange liqueur, then turn the heat off and let the mixture cool.
4. Pour into a piping bag made of baking parchment, create an oval 5 cm/2 in. disc with the bag, and then pipe the disc onto a piece of baking paper or acetate. Put some more melted white chocolate in a piping bag, and then use that bag to write the word "Savarin" on a disc of plain chocolate.
5. Prepare a baking sheet with silicone or parchment paper for the caramel shards. Four tablespoons of water and the sugar should be added to a skillet. Simmer the mixture while stirring until the sugar dissolves. After the sugar has completely dissolved, bring the syrup to a boil without stirring until a sugar thermometer reads 170C. (CAUTION: boiling sugar is extremely hot. Handle very carefully). Pour out immediately onto the prepared tray, then wait for it to set.
7. Use butter to grease a tin or savarin mould. Spoon the batter into the tin after it has risen. Once it has risen to around three-quarters of the way up the tin, cover with oiled clingfilm and let it rise for 45 to 1 hour.
8. Set the oven temperature to 180°/160°.
9. Take off the plastic wrap and bake the savarin for 20 to 25 minutes, or until it is risen and golden brown. Take the tin out of the oven and set it on a wire rack to cool for five to ten minutes.
10. When the savarin is cold enough to handle, remove it from the tin and add half the syrup. Re-insert the savarin gently into the tin to allow it to absorb the syrup and cool entirely. Place the savarin into the remaining syrup and let it soak for five minutes in a roasting pan. Transferring to a serving platter with care.
11. Whip the cream, icing sugar, and vanilla separately for the Chantilly cream until soft peaks form when the whisk is removed. One-third of the Chantilly cream should be placed in a piping bag with a star-shaped nozzle. Refrigerate until you are ready to serve.
12. Segment the zested orange using a good knife. Slice the orange's top and bottom off with care. Slice the skin off the meat using smooth downward motions, then discard. Eliminate any last bits of white pith.
13. Orange slices should be arranged on top of the Chantilly cream that has been piped around the top of the savarin. With the remaining Chantilly cream, fill the savarin, then top with fruit slices. Add the chocolate disc and pieces of caramel on top.