Preheat the oven to 180°C fan bake or 200°C conventional bake.
Cut the top and tail off the beetroots and wrap in tinfoil. Place in the oven and bake for an hour.
Add the carrots to a roasting dish with the garlic, onions, sesame seeds, poppy seeds, honey and 1 tablespoon oil. Mix it all up to coat evenly and season generously with salt and pepper. Bake in the oven along with the beetroot for the last 30 minutes. Remove everything and set aside.
Increase the oven temperature to 200°C fan bake or 210°C conventional bake.
Season the lamb rumps with salt and pepper. Heat a little oil in a frying pan over a high heat. Add the lamb, fat side down, and cook for a few minutes until browned and crispy, and most of the fat is rendered out. Turn over and cook for another couple of minutes to brown the other side. Transfer to a roasting pan and roast in the oven for 13-15 minutes for medium. Remove from the oven, cover loosely with foil and rest for at least 10 minutes before slicing thinly across the grain.
To make the dressing, whisk the ingredients together and season to taste. Mix the spinach and cooked risoni/orzo or couscous in a bowl with half the dressing.