Ingredients

• 4 tablespoons plus 1 cup olive oil
• 4 medium sweet onions, such as Vidalia, thinly sliced
• 6 tablespoons whole raw walnuts
• 2/3 cup grated Parmesan, plus more for sprinkling, optional
• 1/4 cup freshly squeezed lemon juice (about 1 lemon)
• 4 to 5 cloves garlic, smashed
• Sea salt
• 4 cups roughly chopped fresh basil
• 2 cups loosely packed fresh spinach
• 1 cup finely chopped Kalamata olives
• 1 tablespoon balsamic vinegar
• 2 family-size unbaked pizza crusts, white or whole wheat
• 3 medium tomatoes, thinly sliced

Instructions

1. Preheat the oven to 425 degrees F.
2. In a medium saucepan over medium heat, add 2 tablespoons of the olive oil and heat until shimmering, about 2 minutes, then add the onions. Saute on low until the onions are browned and caramelized, 20 to 30 minutes, stirring occasionally. Set aside.
3. Meanwhile, in a food processor, combine the walnuts and 1 cup of the oil and process until smooth, about 1 minute. Add the Parmesan, lemon juice, garlic and 1 teaspoon sea salt and process until blended, about 1 minute. Add 3 3/4 cups of the chopped basil, reserving the remaining 1/4 cup for topping the pizza. Add the spinach and process until smooth, about 1 minute.
4. In a medium skillet over medium heat, add the remaining 2 tablespoons olive oil and heat until shimmering, about 2 minutes. Add the olives and saute for 5 minutes. Remove from the heat, then add the balsamic vinegar and a little sea salt to taste.
5. To assemble the pizzas, place the pizza crusts on two sheet pans or large round pizza pans. Spread the pesto onto the crusts, leaving a 1/4-inch border. Top with the caramelized onions, tomatoes, reserved basil, and olive mixture. Garnish with a little grated Parmesan if you like. Bake until the crusts are golden brown, 8 to 10 minutes.