Heat the olive oil and garlic cloves in a medium frying pan over low heat. Cook until the garlic is golden, about 10 minutes. Add the red pepper flakes and set aside for about 5 minutes to cool briefly.

Combine the red peppers, walnuts, and cooled garlic oil mixture in the carafe of a blender or food processor; add a generous pinch of salt and a crank of pepper. Put the top on the carafe and process until the mixture is smooth, about 30 seconds. Taste and adjust seasoning as desired. (This should yield 2 cups of Red Pepper Pesto. It can be made up to 4 days ahead and stored refrigerated in an airtight container until ready to use. )

Bring a pot of heavily salted water to a boil over high heat. Meanwhile, marinate the tomatoes. Combine the tomatoes, one tablespoon of olive oil, lemon zest juice, and a pinch of salt in a glass or metal bowl. Stir to combine, then set aside while the pasta cooks.

Add the pasta and cook according to package directions when the water boils. Drain the pasta and rinse briefly (it should be lukewarm, not cold, when you mix it with the remaining ingredients).

Place the pasta in a serving bowl, add the red pepper pesto and one teaspoon of the lemon juice, and stir to combine. Taste and add salt and pepper as desired. If you are serving the dish right away (when we think it tastes best), add the olives, tomato mixture (including any accumulated juices), and mozzarella and stir to combine.

Taste and, depending on the acidity of your tomatoes, you may want to add the rest of the lemon juice. Tear up the basil and add it just before serving.