Preheat the oven to 450 degrees(F).
Trim the leaves and stem off of the whole cauliflower as much as possible, but keep it whole.
Now in a small mixing bowl, combine the smoked paprika, brown sugar, ancho chile powder, salt, oregano and cinnamon.
Then add the olive oil and stir to make a spice paste.
Now place the cauliflower on a plate and then rub the spice paste all over the cauliflower. I like to use my fingers so I can get it into all the nooks and crannies. However, you can use a pastry brush if you prefer. Just make sure you spread it all over evenly. Set aside.
Next, add the carrots, potatoes, onions and garlic to a large baking dish. Then sprinkle with a few pinches of salt and pepper. Then pour the broth over the veggies.
Place the whole cauliflower in the center of the veggies in the baking dish. Then roast for 50-55 minutes or until the cauliflower is brown and tender.
Using a spoon or baster get the broth from the bottom of the pan and pour over the top of the cauliflower until you have saturated the cauliflower.
Serve some sliced cauliflower with the roasted veggies and some more broth on top.