In a wide, shallow skillet, melt one tablespoon of olive oil and one tablespoon of butter over medium heat. Add the shallot and cook for 1-2 minutes, stirring constantly, until the shallots have softened. Add the pepper and cook for another minute, until fragrant.
Then, add the rice and cook for another minute, while stirring, so that the rice is coated in the butter and oil. Add the wine and stir until the rice has absorbed most of it. Once the wine has been absorbed into the rice, add 1 cup of warm broth while stirring frequently.
Once that broth has been absorbed, add another cup. A trick to tell when it’s time to add more broth is if the bottom of the pan is exposed when you drag your spoon across the bottom. You will continue to add broth 1 cup at a time while stirring until it has been absorbed into the rice and the rice is just slightly al dente, about 20-22 minutes.
Once the rice has reached the desired doneness, turn off the heat. Stir in the remaining butter, cheese, and mascarpone. Stir until all the cheese has melted. Season to taste with salt and pepper and serve immediately with more cheese on top and lemon wedges on the side.