Step 1 Preheat oven to 200°C. Line 2 large baking trays with baking paper. Place sweet potato on one tray; spray with oil. Put capsicum, onion and garlic on the other tray; spray with oil. Cook both trays for 25 minutes, or until vegetables are tender. Add tomatoes to capsicum tray; cook for 10 more minutes.
Step 2 Place cooked capsicum in a plastic bag for a few minutes to loosen skins, then peel. Place capsicum, onion, peeled garlic, tomatoes and vegetable stock in a food processor; blend until mixture forms a chunky texture.
Step 3 Put mixture in a large non-stick frying pan. Add sugar, basil leaves and vinegar; heat for 5 minutes, or until sauce thickens. Season with cracked black pepper.
Step 4 Cook steaks until done to your liking (following steps on p58). Steam kale until just wilted.
Step 5 Spoon topping onto steaks and garnish with extra basil. Serve with roast sweet potato and kale.