For the pear sponge with saffron, mix eggs, egg yolks, butter, flour, birch sugar and cocoa. Pour into an isi bottle, shoot 3 cartridges.
Spray into a plastic mold about 19 x 19 x 3 cm and cook in microwave for 2 minutes 30 seconds at 600 watts. Allow to cool. Tear into pieces.
Pears, peel, quarter, remove core with knife. Bring white wine, lemon zest, birch sugar and saffron to a boil.
Add pear wedges, cook until soft, about 15 minutes. Let cool in the broth. Pour pears into glasses, place sponge on top, drizzle with brandy, flambé. Serve the pear sponge with saffron.