Preheat the oven to 450°F - 230°C.
Bring a big pot of salted water to a boil.
Rinse and cut the vegetables : Brussels sprouts in halves, broccoli into florets and sweet potato in cubes.
When the water is boiling, pour in the vegetables and blanch for 2 minutes. Remove from the boiling water with a slotted spoon, and plunge into iced water to stop the cooking process. Once completely cold, drain thoroughly.
In a bowl, mix together the vegetables with the olive oil and balsamic vinegar.
Spread on a baking sheet with parchment paper and sprinkle with salt and pepper.
Bake for 35 to 40 minutes, stirring every 10 minutes.
Serve with the hummus and seeds sprinkled on top.