Today, March 11, 2014, is National Blueberry Popover Day. A popover is a light, hollow roll made from an egg typically baked in muffin tins or dedicated popover pans, which have straight-walled sides rather than angled. The name "popover" comes from the fact that the batter swells or "pops" over the top of the muffin tin while baking. The oldest known reference to popovers is in a letter of E. E. Stuart's in 1850. Click Here for a Blueberry Popover recipe.