This recipe makes a lightly seasoned, versatile sauce, allowing the spring like fresh flavor of the ramps to shine through. This sauce is a great white pizza topper, seafood accompaniment, or any other light fare that needs a simple, flavor kick up.
Melt butter over medium heat in medium sauce pan and add chopped onions. Cook onions until translucent, about 2-3 minutes.
Add milk and bring to a simmer over low heat.
Chop green, top parts of ramps into small, half inch pieces. Reserve the bottom half of the ramps; the bulbs, for another use. Add chopped ramps to simmering milk and cook over low heat for 10 minutes, stirring frequently.
Remove pan from heat and pour mixture into food processor or use immersion blender to combine into a light puree.
Add mixture back to saucepan and cook over medium heat for 5 minutes. Remove a small portion (about a 1/4 cup) from pot and mix in separate bowl with flour until smooth and no lumps remain. Add back to saucepan and stir to incorporate.
Stir parmesan cheese in and cook until the sauce reaches your desired consistency. Season with salt to taste.