Preheat the oven to 180 ° C. Cut cauliflower and broccoli into small florets. In a large baking pan lined with parchment paper spread the broccoli, cauliflower, peppers and garlic. Drizzle with olive oil, add salt and pepper. Stir well and spread vegetables on the baking dish. Bake in the middle of the oven for about 30 minutes.
In the meantime, put the two types of quinoa in a colander and rinse well with water. Put the 4 cups of water in a saucepan and when it has boiled, add the quinoa with some salt. Cook for about 10 minutes until all water is absorbed. Cover the pot with a towel and set aside.
To make the sauce, put all the ingredients in a mixer and blend for at least 1 minute. Try taste and if necessary adjust the quantities of materials.
When the vegetables are cooked, remove the garlic and place them in the pot with the quinoa and stir. Serve in deep dishes and drizzle with the tahini sauce and pine nuts.