Heat the oil in a pot over medium heat, add the onion, celery, garlic, and carrot and saute until the celery starts to soften and the onion is translucent. Stir in the flour until fully combined.
Add the rice and broth to the pot, cover with a lid, and bring to a simmer. (Refer to the instructions on the package for cooking the rice). Simmer until the rice is tender.
Once the rice is tender, stir in the cream. Bring the soup back to a simmer. Stir in the lemon juice a little at a time while tasting so you don't add too much, season with salt and pepper to taste as needed. Remove from the heat and stir the parsley into the soup.Flavor should be a vibrant hint of lemon, not overpowering