Warm your broth.In a medium sized saucepan, bring broth to a simmer. Lower heat and keep stock heated on low.
In a large saucepan over medium heat, add in 2 Tbsp. butter and the oil. Sauté the shallot and onion (stirring often) and cook until softened, about 4-5 minutes.
Add in diced mushrooms and garlic. Cook for 6-7 minutes, or until mushrooms cook down and begin to release their moisture. Stir occasionally.
Add in arborio and remaining butter and stir rice until well-coated, about 2 minutes. You will notice the rice becoming translucent but the center is still opaque.
Slowly add the warm broth in increments, ~ 1/3 cup at a time. Stir regularly between additions, and allow the broth to fully absorb before adding the next ladle of broth. Repeat until the rice is al dente and the broth is creamy, about 20 minutes. You'll know when the risotto is ready when you run your spatula through the risotto and the risotto flows slowly back to fill in the space. Also be sure to taste it! Should be al dente (a little bit of chew).
Remove pan from heat, stir in rosemary, Parmesan and salt and pepper. Serve warm.
Use a freshly grated block of Parmesan, it is much better than the pre-grated stuff. If you don't have a shallot, use 1 medium onion. We love the flavor of shallots add so we use both, but they can be used interchangeably. Be sure to use Arborio rice, Carnoroli, or Vialone nano rice. These types of rice hold up well to the constant stirring creating the perfect risotto.