<http://schema.org/recipeInstructions>
" Make the frosting: In a large stainless-steel bowl placed over a pot filled with 1 inch of simmering water, place the egg whites and sugar. Use a whisk to beat the mixture until it is very hot to the touch (about 160 degrees F). Remove from heat and, using a mixer set on high speed, immediately begin whipping the mixture until it is cool, thick, and glossy and has tripled in volume -- about 5 minutes. Reduce mixer speed to medium and add the butter -- about a quarter cup at a time -- allowing 5 to 10 seconds in between each addition. Add the lemon zest and lemon juice and continue to beat until smooth and fluffy."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.countryliving.com/food-drinks/recipes/a1207/lemon-buttercream-3330/>