Preheat the oven for the orange dust (electric cooker: 75 °C/circulating air: 50 °C/gas: see manufacturer). Line baking tray with baking paper. Rinse oranges in hot water, dab dry. Peel the skin of 1 orange in fine strips using a pestle ripper, bring to the boil with liqueur.
Pour through a fine sieve, catch the liqueur, put aside. Drain the orange peel and spread it on the tray. Dry in a hot oven for about 30 minutes, take out, let cool down.
For the batter groove cups, place them on a tray (or place paper cups in the recesses of a muffin baking tray, 12 recesses). Preheat oven (electric oven: 180 °C/circulating air: 155 °C/gas: see manufacturer).
Break chocolate into pieces. Melt with butter and honey in a hot water bath, then lift out. Finely grate the zest of the remaining orange into the chocolate butter. Stir in 1 tablespoon of the liqueur you have collected.
Mix eggs and sugar. Stir in warm chocolate-orange butter. Sift the flour on top and stir in briefly. Spread 2-3 tablespoons of dough (it is quite liquid!) into each of the moulds. Bake in a hot oven for about 12 minutes (the surface of the cakes should still shine in the middle).
Remove and allow to cool briefly.
For the orange dust, crush the dried orange peel finely in a mortar. Carefully remove the cakes from the moulds. Dust with orange dust through a fine sieve and serve immediately.