Hi this may be to late for you but I have descovered that I love mashed Cauliflower or Mashed Pumpkin with roast meat. I make the gravey and reduce it as much as I can to get a nice rich flavour then whip in a table spoon or 2 of the pureed veg this thickens the gravey perfectly.

This come from when I was growing up and my dad often used mashed potato to thicken soup and stew

Hope this helps

Fluffy