Add 2 tablespoons olive oil to a large saucepan over medium heat for about 2 minutes. Add shrimp to the pan. Season to taste and cook until they are pink and opaque, stirring occasionally. This should take about 5 minutes. Remove from the pan and set aside.
To the same pan, heat the remaining tablespoon of olive oil and butter. Add the shallots and garlic to the pan and cook for about 3 minutes. Add the rice and cook until slightly translucent for about 2 minutes, stirring often.
Add 1 cup of the stock and cook, stirring, until it has been absorbed by the rice. Continue to cook and stir, adding ½ cup of the stock at a time as the liquid is absorbed by the rice. You may not need to use all the broth.
When the rice is just about tender, after about 20 minutes of stirring and adding stock, use your fingers to break up the saffron threads as you add them to the rice. Stir in the parmesan cheese. Add the shrimp back to the pan. Add more stock as needed, until the rice is just tender and creamy. Serve immediately.