1.Oil a 19cm x 29cm slice pan.
2.Place the water in a large saucepan and bring to the boil. Gradually add polenta to liquid, stirring constantly. Reduce heat and continue stirring for 10 minutes or until polenta thickens. Stir in butter and cheese then spread polenta into slice pan; cool 10 minutes. Cover and refrigerate overnight.
3.Combine 2 tbsp vinegar, wine, garlic with steaks in a large bowl. Cover and refrigerate overnight.
4.Turn polenta onto a chopping board; trim edges. Cut polenta into six squares and cut each square in half diagonally to form two triangles. Cook polenta triangles on a heated oiled barbecue grill plate until heated through. Cover to keep warm.
5.Meanwhile, remove steaks from marinade; discard marinade. Cook steaks on the heated oiled barbecue grill plate for 4 minutes each side or until cooked as desired.
6.To make rocket salad, place oil, mustard, sugar and remaining vinegar in a screw-top jar. Shake well. Place rocket and half the dressing in a large bowl; toss gently to combine. Reserve remaining dressing to serve.
7.Serve steaks drizzled with reserved dressing, with polenta triangles and salad.