Drain and rinse two 15-ounce cans cannellini beans; set aside 1/2 cup for garnish. Puree the remaining beans in a food processor with 1 minced garlic clove, the juice of 1 lemon, and salt and pepper. Slowly drizzle in 1/2 cup olive oil with the motor running, then transfer the dip to a bowl. Toss the reserved beans with 1 diced roasted red pepper, 3 tablespoons olive oil, 1 tablespoon each chopped parsley and basil, and salt and pepper. Spoon over the dip and serve with pita chips.