Preheat the oven to 200 degrees celsius (400 degrees Fahrenheit)
Cut the cauliflower head into bite sized florets and place on a baking sheet, drizzle with 1 tbsp olive oil and bake in the oven for 20 to 25 minutes until the cauliflower florets are slightly tender and golden but not mushy. Set aside and allow to cool.
Bring a shallow pan of water to a boil and add the asparagus and green beans. Cook for 4 to 5 minutes. While the beans and asparagus are cooking prepare an ice bath by filling a large bowl with ice and cold water.
As soon as the vegetables are done, plunge them in the ice bath to completely cool.
In a bowl or blender mix all of the ingredients for the vinaigrette. Set aside.
In a large serving bowl combine the asparagus, green beans, halved cherry tomatoes, cauliflower florets, red onion and chopped fresh basil. Top with the vinaigrette and toss until well combined. Serve