Squeeze all of the water from the spinach. In a large saucepan, heat the oil over medium heat. Add the shallots and cook, stirring, until softened, about 2 minutes. Add the flour to the pan and cook, stirring, for 30 seconds. Add the low-fat milk and broth and cook, scraping up any bits from the bottom of the pan. Bring to a simmer and cook 2 minutes.
Add the spinach and simmer until tender, about 5 minutes. Stir in the evaporated milk and nutmeg, and season with salt and pepper.