Preheat the oven to 220C, fan-forced. Line an oven tray with baking paper. Cut the unpeeled potatoes into 2cm-thick wedges. Put the wedges on the lined tray, drizzle with 2 tsp olive oil, season with salt and pepper and toss to coat. Roast for 25 mins or until golden and tender.
Step 2 — Prep ingredients
Meanwhile, thinly slice the onion and tomato. Crumble 1 stock cube* into a heatproof jug, add 200ml boiling water and stir to dissolve.
Step 3 — Make French dip
Heat 2 tsp olive oil in a medium saucepan over medium-high heat. Cook the onion and a pinch of salt, stirring occasionally, for 8-9 mins until caramelised. Add 3 tsp plain flour and cook, stirring, for 1 min. Gradually add the stock (see Kitchen 101) and bring to the boil. Cook, stirring, for 2 mins or until slightly thickened. Remove the pan from the heat.
Step 4 — Cook patties
Heat 2 tsp olive oil in a medium frypan over medium-high heat. Add the beef patties to the pan, season with salt and pepper, then cover and cook for 3-4 mins each side until cooked through. Remove from the pan. Halve the buns. Put the buns, cut-side up, on an oven tray and toast for 5-6 mins until golden.
Step 5 — Serve up
Stir 1 tsp dijon mustard and 1 tsp balsamic vinegar into the French dip. Taste, then season with salt and pepper. Spread the bun bases with the aioli. Layer with the beef patties, tomato and rocket, then sandwich with the bun tops. Divide the burgers, wedges, French dip and remaining rocket among plates. Enjoy!
Step 6 — Kitchen 101
The secret to smooth French dip? Add the stock gradually, stirring constantly, to achieve a creamy consistency before adding more stock. If lumps form, use a whisk and more elbow-grease, and whisk until smooth.