How to Make It
Preheat the oven to 350°. Line 2 cookie sheets with parchment paper.
In a standing electric mixer, beat the almond paste and sugar for 1 minute. Scrape down the bowl and beat for 30 seconds longer. Beat in the egg whites, 1 tablespoon at a time, until well blended. Scrape down the bowl and beat for a few seconds; the batter will be soft but not runny.
Scrape the butter into a pastry bag fitted with a #5 round tip (about 1/2 inch). Pipe 1 1/4-inch rounds about 1 1/2 inches apart on the prepared cookie sheets. Sprinkle the pine nuts all over the tops and sides of the mounds. Bake for 20 minutes, turning the sheets once, until the cookies are golden brown. Slide the parchment paper onto a rack and let the cookies cool completely. Remove the cookies from the paper and serve.