Preheat your slow cooker to low or preheat the oven to 150C, fan-forced. Coarsely chop the onion. Put the beef in a bowl. Scatter with 1 tbs plain flour, season with pepper and toss to coat.
Step 2 — Brown beef
Heat 2 tsp olive oil in a medium frypan (if using a slow cooker) or a medium flameproof casserole dish over high heat. Shake the excess flour from the beef, reserving the flour. Cook the beef, turning regularly, for 3-4 mins until browned. Remove from the heat.
Step 3 — Slow cooker method
If using the slow cooker, combine the beef, onion, worcestershire sauce, barbecue seasoning, reserved flour, 2 tbs tomato sauce and 300ml boiling water in the slow cooker bowl. Cover and cook on low for 8 hours. Coarsely shred the beef in the slow cooker bowl. Taste, then season with salt and pepper.
Step 4 — Oven method
If using the casserole dish, add the onion, worcestershire sauce, barbecue seasoning, reserved flour, 2 tbs tomato sauce and 410ml (1⅔ cups) boiling water to the beef in the dish and stir to combine. Bake, covered, for 4½ hours or until the beef is tender. Coarsely shred the beef in the dish. Taste, then season with salt and pepper.
Step 5 — Toast buns
About 15 mins prior to serving, if using the slow cooker, preheat the oven to 200C, fan-forced. Line an oven tray with baking paper. Cut the buns in half. Coarsely grate the cheese. Put the buns, cut-side up, on the lined tray. Scatter the cheese over the cut side of the bun tops. Bake for 6 mins (or 10 mins at 150C if using the oven method) or until the cheese is melted.
Step 6 — Serve up
Combine 2 tsp olive oil and 1 tsp red wine vinegar in a large bowl and season with salt and pepper. Add ranch salad and toss to coat. Spread bun bases with burger sauce. Layer with some of the salad and, using a slotted spoon, the beef. Sandwich with bun tops. Divide beef sauce among bowls. Serve burgers with remaining salad and sauce for dipping. Enjoy!