Preparation Heat 3 tablespoons oil in large skillet over medium-high heat. Add pancetta; sauté 3 minutes. Add onions, garlic, lemon juice and fennel seeds; sauté until onions begin to brown, about 10 minutes. Reduce heat to medium; cover and cook until onions are tender, stirring occasionally, about 20 minutes. Remove from heat. Stir in vinegar. Season with salt and pepper. (Can be made 1 day ahead. Cover; chill. Rewarm over medium-low heat before continuing.) Drizzle each toast slice with 1 teaspoon oil. Divide onion mixture among toasts. Sprinkle with parsley and serve.
Preparation Heat 3 tablespoons oil in large skillet over medium-high heat. Add pancetta; sauté 3 minutes. Add onions, garlic, lemon juice and fennel seeds; sauté until onions begin to brown, about 10 minutes. Reduce heat to medium; cover and cook until onions are tender, stirring occasionally, about 20 minutes. Remove from heat. Stir in vinegar. Season with salt and pepper. (Can be made 1 day ahead. Cover; chill. Rewarm over medium-low heat before continuing.) Drizzle each toast slice with 1 teaspoon oil. Divide onion mixture among toasts. Sprinkle with parsley and serve.