Preheat the oven to 425 degrees F. Rinse off head of cauliflower and cut off the green leaves and most of stems. Drain well. Cut into little florets. Place a handful of cauliflower florets into the Vitamix or food processor (about a cup or so) and put the lid on. Turn the machine on to variable speed 2 and press the cauliflower into the blades with the tamper. After about 5 seconds the cauliflower should be in little rice shapes. If you are using a food processor, just pulse a few times until the cauliflower looks like rice.Repeat in small batches until the whole head is riced.
Spread out the cauliflower rice on a sheet pan lined with parchment paper. Drizzle with a bit of olive oil, and some salt and pepper. Use a wooden spoon to gently toss. Place in the oven and roast for about 25 minutes, or until the top start to turn golden brown.
Toss the small cubes of golden beets with some olive oil and salt, place in another pan, and stick in the oven. Roast for 25 minutes as well.
Take the cauliflower and beets out of the oven. In a large bowl, toss the cauliflower and beets with the mint, parsley, some more olive oil and a generous squeeze of lemon (I use lots of lemon!). Season with salt and pepper to taste.