Smoked Salmon and Artichoke in Alfredo Sauce

Heat butter and olive oil together in a large skillet over medium heat; cook and stir onion and salt until translucent, 5 to 10 minutes. Add garlic and cook until fragrant, about 1 minute. Reduce heat to medium-low; add artichoke hearts, wine, chicken broth, lemon juice, lemon zest and red pepper flakes; simmer until liquid is reduced and thickened into a sauce, about 10 minutes. Mix salmon, cream, Parmesan cheese, salt, and pepper into sauce; simmer until thickened, about 5 minutes.