Peel and mince the garlic.
In a large skillet, heat the olive oil over medium heat.
Add garlic and sauté for 2 minutes.
Add the kale and cook, stirring constantly.
The kale will become bright green when it is wilted.
Add the kale to a blender or food processor, pour in 1/4 cup hot water (more if needed) and pulse until pureed.
In a large soup pot on medium high heat, cook the onion in butter until it begins to soften.
Sprinkle in the flour and stir to combine.
Add the milk, stirring occasionally.
Add salt, pepper, and cayenne and stir.
Pour in pureed kale, then cook another 3 to 5 minutes until thickened.
Stirring constantly over medium heat for 5 minutes.
Check seasonings, adding more salt, pepper, or cayenne as needed.
Serve in a bowl topped with a little grated Parmesan cheese.