Preheat your oven to 450º F (230º C). Line a rimmed baking sheet with high-heat-resistant parchment paper or foil.
Place peppers and tomatoes on the prepared baking tray. Lightly drizzle with 3 tablespoons of olive oil. Let the veggies roast under the broiler for 20-25 minutes, giving a stir every 5 minutes, until they are soft. Remove from the oven and transfer the roasted peppers and tomatoes to a cutting board. Let the roasted pepper sligly cool and then chop them into 1/2-inch slices. Set aside. Pro Tip: You may use store-bought roasted peppers and tomatoes to skip this step and save time. Heat 3 tablespoons of olive oil in a large skillet over medium heat. Add the onion, leek, green beans, and carrot, and sauté for 3 - 4 minutes or until fragrant. Add the garlic and sauté for 1 more minute.
Add the rice, then cook and stir for 3 minutes, or until the rice is opaque.
Add the vegetable broth and bay leaf to the skillet. Crush the saffron threads between your fingers, then add them to the skillet with the paprika. Season with salt and pepper, then stir until everything is combined. Bring to a boil, then reduce heat to medium-low and cook, simmering, for 10 minutes, or until the rice has absorbed most of the broth and the rice is almost tender.
Reduce heat to low, cover with foil or a lid, and cook for 10 minutes or until tender.
Remove from heat and let stand, covered, for 10 minutes.
Uncover and top with roasted peppers and tomatoes, and olives. Drizzle with more olive oil if desired. Serve immediately.