First i would get a center punch and tap that right in the middle of that broken bolt.. Then drill into it with something smaller in diameter.. Make sure you are centered well.. Then get you an easy out or a reverse threaded drill bit and go slow.. Should back right out.. Could even apply a lube or cutting oil to the bolt area threads

X2

Might spray some PB Blaster on it and let it soak a day or so and I'd also put on the kicker when your attempting to undo the bolt so you've got something to stop it from rotating.