Cut nectarines into thin wedges and chop mint. Put the butter in a pan, add the honey and mint. Sauté nectarine wedges in around 2 minutes (return at the middle of the time).
Put the knob of butter in a pan. Mix sugar, egg and milk. Dip the brioche slices a few seconds in this mixture (do not soak too long for the brioche keeps its consistency). Fry in pan about 7min turning at the middle of the time).
Arrange the slices on a plate and place the roasted nectarine above.