Heat the oven to 200C/180 fan/gas 6. Slice the potatoes/cauliflower into chips. Spread the chips on a large non-stick baking tray and toss in oil, salt and pepper. Lie them flat in a single layer and bake for 45 minutes, turning every so often, until golden and crisp on the outside. Season with salt.
While the chips are cooking make the toppings.
Brown the mince and onion in a pan. Blend the sachet with the water and add to the mince, along with the tinned tomatoes and beans.
Bring to the boil, stirring continuously. Reduce heat, cover and simmer for 20 mins until cooked.
Spoon the chilli over the chips and sprinkle the cheese over. Place back in the oven/grill until the cheese is melted and golden (approx. 10 mins).
To serve, scatter the salsa and spring onions on top and dollop o the sour cream.