Place scotch fillet on a plate. Pound garlic, lemongrass, chilli, coriander root and chopped stems in a mortar and pestle until it forms a paste. Stir oil into paste. Spread paste over beef and leave to marinate while you prepare the salad ingredients.
Chargrill beef on a bbq hot plate or chargrill pan for 3 minutes per side. Rest and slice. Cut kernels off corn cob.
Place wombok, corn kernels, and kale in large bowl. Mix fish sauce, lemon and brown sugar together. Drizzle half the sauce over the salad and toss to combine. Pour remaining sauce over rested sliced beef.
Top salad with beef, shallots, peanuts, coriander leaves and lemon wedges.
