Leftover roasted vegetables need very little to be turned into a delicious puréed soup. You can add pesto, nut butter, or silken tofu while blending for extra flavor or texture.
1 Tbs. olive oil
1 small onion, thinly sliced (1 cup)
3 cups firmly packed roasted vegetables
Heat oil in medium saucepan over medium-high heat. Add onion, cook 7 to 9 minutes, or until just beginning to brown.
Add vegetables and 2 cups water, and bring mixture to a simmer. Reduce heat to medium, and cook 15 minutes. Cool to room temperature, then purée until smooth. Add more water, if desired, and reheat before serving.