1 tablespoon olive oil
2 medium white or yellow onions, chopped
2 bunches asparagus, chopped
1/2 head cauliflower, cut into florets
2 cups low-sodium chicken or vegetable stock
Salt and pepper to taste
1 cup frozen peas, thawed
2 tablespoons Dijon mustard
Zest of 1 large lemon
1 tablespoon finely chopped fresh mint
1. Heat olive oil over medium heat in a large pot or saucepan. Add onions and saute for 6 to 7 minutes, until light brown. Add asparagus and cauliflower and stir for 5 minutes. Add stock and salt, bring to a simmer, cover, and cook for 25 minutes.
2. Let mixture cool slightly, then, using an immersion blender, blend until no chunks remain. (Or blend in two batches in a blender for about 2 to 3 minutes.) Return sauce to the pot over medium heat and add peas, cooking for 3 to 4 minutes, until heated through.
3. Remove from heat and add Dijon and lemon zest, stirring well. Season with additional salt and pepper, if desired.
4. Serve over freshly cooked pasta and top with fresh mint.