Add all of the ingredients except the butter to a blender in the order listed. cover and pulse until just combined and smooth.

Cover and refrigerate the batter in the blender jar for 1 hour.

Preheat the oven to 400°F. Cover a baking sheet with a silpat or foil and place on the bottom oven rack.

Remove the batter from the refrigerator and blend the batter again briefly to mix it.

Cut the butter into tablespoons and then cut the tablespoons into thirds until you have 12 pieces. Place a piece of butter into each popover cup, then place the pan into the oven to melt, about 5 minutes.

When the butter is melted and the pan is heated, remove it from the oven. Evenly divide the batter between the 12 popover cups, about ½ cup each. The cups should be about halfway full. Bake for 20 minutes.

Reduce the heat to 350°F and bake another 10 to 15 minutes until they’re firm and golden brown. Remove from the oven and serve immediately.