Preheat oven to 350 degrees F. Grease two 5 ounce ramekins and set aside. Place a steam insert into a medium pot and fill with enough water so it’s not touching bottom of steamer.
Add potatoes and cauliflower to steamer insert, cover with lid and cook over medium until tender about 8 to 10 minutes.
Remove and add to mixing bowl along with garlic, milk, salt and pepper then using a hand held mixer beat until smooth. Place one slice of cheese into bottom of ramekins, spoon puree evenly then top with second slice of cheese.