Preheat BBQ to a medium heat, add eggplants and cook for 25-30 minutes turning regularly until very tender.
Cool the eggplant slightly, slit lengthways and scoop out the flesh. Place in a colander for at least three minutes to drain excess liquid. Transfer the flesh to a food processor along with the lemon juice, tahini, garlic, olive oil and salt and pepper, pulse until just smooth.
Preheat BBQ on a high heat, season steaks well and cook for 3 to 4 minutes each side for medium. Serve steak with baba ganoush and barbecued asparagus.