Start by making the French toast. Melt the butter very briefly in the microwave, and then beat together with the egg, 1 tbsp icing sugar and a squeeze of fresh orange juice.
Remove the crusts from the bread, and soak in the butter and egg mixture, turning over after 30 seconds. Melt a little more butter in a frying pan on a medium heat, and then add the bread (allowing excess egg to drain off first). Fry until golden underneath and then turn over gently. Remove to a plate once cooked, and dust with icing sugar.
To make the cocktail, combine all the ingredients in a cocktail shaker (or, if you don?t have one, a large jar with a lid) with plenty of ice, and shake until really cold. Strain into two martini glasses.
Finally, if you want to garnish, cut two triangles out of the French toast. Cut a slit inwards to the middle from one side, on each triangle, and use this to perch the triangle on the rim of the glasses. Serve the extra toast on the side. Cheers!