Before starting, preheat the oven to 450°F. Wash and dry all produce. Finely chop 1 tsp rosemary leaves (dbl for 4 ppl). Cut potatoes into 1/2-inch thick wedges. Toss potatoes and rosemary with 1 tbsp oil (dbl for 4 ppl) on a parchment-lined baking sheet. (NOTE: For 4 ppl, use 2 baking sheets, with 1 tbsp oil per sheet.) Roast in the middle of the oven, flipping halfway through, until golden-brown, 25-28 min. (NOTE: For 4 ppl, roast in the middle and the bottom of the oven, rotating sheets halfway.)

While potatoes roast, thinly slice tomato. Cut halloumi into 1/4-inch thick slices. Rinse halloumi under cold water and pat slices dry with paper towels. Stir together basil pesto and mayo in a small bowl. Set aside.

Heat a large non-stick pan over medium-high heat. When hot, add halloumi to the dry pan. Cook, until golden-brown, 1-2 min per side. (NOTE: Cook halloumi in 2 batches for 4 ppl.)

While halloumi cooks, halve buns and arrange them on another baking sheet, cut-side up. Toast in the top of the oven, until golden-brown, 3-4 min. (TIP: Keep your eye on them so they don't burn!)

Spread basil aioli over cut sides of buns, then top with spring mix, halloumi and tomato slices. Divide between plates and serve potato wedges alongside.