Roast the broccoli: Preheat the oven to 400 degrees F. Add the broccoli florets, oil and a large pinch of salt to a rimmed baking sheet lined with parchment paper. Toss to combine, and spread out in a single layer. Roast for 20 minutes, stir and roast until the broccoli is browning, 10 minutes more. Remove from the oven, and set aside to cool.
Make the dressing: Combine the mustard and vinegars in a small bowl. Drizzle in the oil, salt and pepper, and stir until smooth.
Assemble the salad: Combine the roasted broccoli, tomatoes, avocado and onions in a large bowl, and toss to combine. Divide between 2 bowls, drizzle with dressing and serve immediately.
The broccoli stems can be peeled and steamed as a side dish or used in soups or stir-fries. Or add them to your green juice for a spicy, nutritional boost.
Recipe courtesy of Amy Chaplin