Caution … this dish is ridiculously rich and delicious. And easy. And did we mention it freezes well?
Shuck corn. Slice kernels off cob into a bowl. Holding cob over the same bowl, use the back of a knife to scrape down cob, releasing pulpy corn bits and milky juices.
In a medium-size saucepan over medium heat, sweat onion and garlic in oil until translucent, about 5 minutes. Add corn, season with salt, and stir well. Cook about 2 minutes longer. Add cream and cook until most of cream is reduced and mixture thickens, about 15 minutes.
Stir in butter. Transfer about half of corn mixture into a food processor or blender and purée. Return purée to pan and stir well. Serve warm.