Top bread with Parmesan, place on a baking sheet and bake until the bread is crispy and the cheese is melted, 5 to 7 minutes.
Heat oil in a large nonstick skillet over medium-high heat. Add garlic and cook, stirring constantly, until fragrant, 30 seconds to 1 minute. Stir in tomatoes and beans and cook, stirring often, until the tomatoes are beginning to soften and the beans are heated through, 2 to 4 minutes. Stir in spinach, pepper, salt and broth and cook, stirring constantly, until the spinach is just wilted, 2 to 3 minutes. Remove from the heat and stir in basil (or pesto). Spoon the bean-and-spinach mixture over the Parmesan toasts and serve hot.