Melt the white chocolate and mix with the sunflower oil. Transfer to an electric airbrush. Take the panna cotta ring out of the blister and put on a tray and brush the frozen ring with the chocolate. Cover with plastic and defrost in the fridge or store in the freezer.
Beat the butter together with the sugar in the machine. Add the egg white bit by bit until it’s a homogeneous mass. Add the flour and let the batter rest in the fridge for 4 hours. Use a mold to bake the cookie in the oven at 180 ˚C for 6-8 minutes. Store in an airtight container.