Melt the butter and olive oil in a large pan set over medium heat. Add the onions and cook, stirring frequently, for 15 minutes, or until the onions soften and begin to brown. Add a generous pinch of salt; continue to cook the onions for 20-30 minutes, or until they are very soft and deeply browned. If the pan gets too dry, add a tablespoon or two of water to keep the onions from burning.

Remove the onions from the heat and let them cool to room temperature. Stir them into the softened goat cheese. Use the goat cheese spread immediately or refrigerate for later.

Spread 4 tablespoons of the caramelized onion spread onto each wrap. Top with turkey and vegetables. Wrap tightly, then cut each wrap in half. Serve immediately, or wrap tightly in foil and chill until ready to eat.