The first time I made these garlic mashed potatoes, I didn’t know what my husband Jack would think of them. See, Jack grew up eating his Uncle Billy’s mashed potatoes, and he still reminisces about them. They were creamy, fluffy, and rich with (lots of) melted butter and (lots of) sour cream.  These garlic mashed potatoes aren’t exactly like Uncle Billy’s. Instead of dairy, olive oil and starchy potato cooking water give them an amazing creamy texture, and roasted garlic fills them with rich, nutty depth of flavor. When I tried them, I thought they were delicious, but Jack’s opinion would…