Step 1 Preheat oven to 200°C. Put potato, soy sauce and maple syrup in a large bowl; toss to coat. Line a baking tray with foil, then with baking paper (wrap it over tray edges). Add potato and any remaining syrup mixture. Roast for 30 minutes, or until potato is golden and cooked through.
Step 2 Meanwhile, bring a small saucepan of water to the boil; cook asparagus for 1–2 minutes, or until just tender. Refresh in cold water and drain.
Step 3 Whisk lemon juice, olive oil and mustards in a large bowl. Cook rice according to packet instructions. Place potato, asparagus, rice, celery, parsley, chives, spinach and pecans in bowl. Toss gently and serve.