Broccoli's impressive nutritional profile (think folate, vitamins C and A, fiber, phytochemicals) puts it high on the list of foods to eat more of, an inviting task when you toss it with crunchy pine nuts, soft, sweet onions and tangy balsamic vinegar.
Toast pine nuts (or almonds) in a medium dry skillet over medium-low heat, stirring constantly, until lightly browned and fragrant, 2 to 3 minutes. Transfer to a small bowl to cool.
Add oil to the pan and heat over medium heat. Add onion and salt; cook, stirring occasionally, adjusting heat as necessary, until soft and golden brown, 15 to 20 minutes.
Meanwhile, steam broccoli until just tender, 4 to 6 minutes. Transfer to a large bowl. Add the nuts, onion, vinegar and pepper; toss to coat. Serve immediately.