Place the sausage into a food processor and pulse until it is minced.
Heat the oil in a large skillet over medium-high heat.
Add the meat and garlic and cook for 1 minute, stirring.
Bring a large pot of salted water to a boil.
Working in batches, lay out the wonton wrappers and place one tablespoon of the meat into the middle.
Dip your finger in warm water and run it along the edges of the wrapper.
Take one corner of the wrapper and fold the filling, forming a triangle.
Push down on the meat filling to get as much air out as possible, then pinch the edges to seal.
Lower 5-6 ravioli at a time into the boiling water and boil for 1 minute. I found that using a spider (or large slotted spoon) helped make sure that the ravioli don't fall apart.
Remove cooked ravioli to a plate but do not stack them or they will stick together.
Continue working in batches until all of the ravioli are cooked.
Serve with the sauce.
For the sauce
Melt the butter in a medium saucepan over medium-high heat.
Whisk in the flour and continue cooking for 1 minute.
Slowly add the milk while whisking.
Reduce the heat to a simmer and continue whisking until the sauce is as thick as you like.