Preheat the oven to 425F and line two cookie sheets with parchment paper for easy cleanup. Chop or dice the vegetables and place on the sheets. Drizzle olive oil over the vegetables and stir around until the vegetables are evenly coated. Lightly sprinkle with salt and pepper and stir again. Place in the oven for 40 minutes, rotating at 20 minutes to ensure even roasting.
While the vegetables are roasting, make the lemon dressing by combining the olive oil, lemon juice, and salt and pepper. Taste and adjust accordingly.
After 20 minutes of roasting, rotate the cookie sheets and begin cooking the orzo. Melt the butter over medium heat and then add the orzo. Roast the orzo for 1-2 minutes until toasty and add in the vegetable broth. Bring to a simmer, turn to low, cover and cook for 15-18 minutes until the orzo is done.
Combine the orzo, roasted vegetables, dressing, and pine nuts.