place the chicken stock in a large pot and warm it on low.
In a large saucepan heat the butter and oil together until butter is melted. add the shallots and garlic and cook about 6 minutes. Add the rice and stir until slightly browned. Add the vodka and stir until all is absorbed. Add the lemon juice and let most evaporate. Add the broth one ladle at a time stirring constantly.
Continue ladling in the broth and stirring until rice is creamy and al dente. About 25 minutes. Fold in the lemon zest and Parmesan cheese. Season with salt to taste.