Place a rimmed baking sheet in the lower third of the oven; preheat to 450 degrees F. Make the pesto: Pulse the parsley, basil, scallions, whole garlic, Worcestershire sauce, lemon zest and the juice of 1 lemon in a food processor. With the motor running, add 1/4 cup olive oil. Refrigerate 3/4 cup of the pesto for Risotto with Pesto and Peas. Coat the pork with 1/4 cup of the remaining pesto. Mix the remaining 1/2 cup pesto in a small bowl with 1 tablespoon hot water and the remaining lemon juice; season with salt and pepper. Heat 1 tablespoon olive oil in a large skillet over medium-high heat. Add the pork and brown all over, about 4 minutes. Transfer to the hot baking sheet and roast until a thermometer registers 145 degrees F, about 15 minutes. Meanwhile, cook the polenta as the label directs. Heat the remaining 1/2 tablespoon olive oil in the skillet over medium heat. Add the sliced garlic and cook 1 minute. Add the spinach, 3 tablespoons of the pesto mixture and 1/4 cup water; cook, stirring, until wilted, 3 minutes. Slice the pork; serve with the polenta, spinach and remaining pesto mixture. Season with salt and pepper.