This recipe makes enough cookies for 18 napoleons.
Heat oven to 375 degrees. Line two cookie sheets with parchment paper. In small saucepan over low heat, melt butter.
In electric mixer with whisk attachment, beat egg whites and sugar on medium speed about 30 seconds. Add melted butter, cream, and almond extract; beat until combined, about 30 seconds. Sift together flour, cocoa, and salt; add to mixture; beat until combined. Transfer to airtight container.
Spoon 1 1/2 teaspoons batter onto lined baking sheet. Using back of spoon or fingertips, spread into thin circle, 3 inches in diameter. Repeat to fill baking sheet. Bake until edges are golden brown, 6 to 7 minutes. Monitor cookies while baking; they burn easily. Using thin spatula, quickly and carefully transfer cookies to rack to cool. Repeat until all batter is used, staggering two baking sheets in the oven. Store tuiles in airtight container until ready to assemble.