Add 2 tablespoons of butter to a pot over medium heat. Let melt completely. Add garlic and cook for 30 seconds.
Add in rice and saute in butter for 1 minute. Then pour in white wine.
Let simmer, stirring occasionally, for 3-4 minutes, or until liquid is mostly absorbed.
Add 1/2 cup of chicken broth. Let simmer until absorbed. Continue to do this with 2 cups of chicken broth (so 4 times total).
After 2 cups of broth (and 1 cup wine) have been absorbed, taste rice for doneness. It should be slightly chewy, but still firm - you don't want soggy rice! If it is not done, add another 1/2 c. broth, let it absorb, and then check again.
While rice is cooking, heat a large skillet to medium-high heat. Add the steak and let sear - 2 minutes on each side. Then continue stirring and sauteing until cooked through.
Remove steak to a plate or bowl. Add 1-2 tbsp of olive oil to pan, swirl and let heat. Add mushrooms and peas and cook until tender - 2-4 minutes, depending on the texture you like.
Add steak back to skillet, along with cooked rice. Stir to combine. Add parmesan, sour cream, and - if needed - 1/4 c. of chicken broth. Stir slowly to combine, letting parmesan fully melt.
Season with salt and pepper to taste. Top with more shredded parmesan if desired, for serving.