Season both sides of the medallions with salt and pepper
heat some olive oil in a large pan on high, add 1 tbsp of butter and let it melt. Once the butter is bubbling add the medallions, you may need to do it in batches depending on pan size
Sear the medallions 2 minutes per side until a brown crust forms. Remove from pan, leaving the juices
add the other tbsp of butter to the pan and allow to melt. Add the onions and garlic and saute for about 1 minute
Add the wine and bring to a rolling boil, scraping the pan with a flat wooden spoon. Once most of the wine has evaporated, add the cream and blue cheese
once the blue cheese has melted bring everything to a simmer, return the medallions to the pan, cover and cook 3-5 minutes until done (the center of a medallion should be 145F / or a very light pink)
Serve the medallions over the zucchini noodles and spoon with sauce and garnish with parsley