Beat butter. Add sugar and eggs and continue beating for at least 3 minutes. Add salt, vanilla, and about half the flour that has been combined with the baking powder. Beat with spoon only until smooth. Add almonds and beat until blended. Then add rest of the flour, beating with spoon until well blended. (A light texture is desired.)

Divide dough into 4 uniform portions. Form each portion into a roll on floured cloth. Place in a well-greased and floured baking sheet that measures about 12 x 18 inches. Pull roll to fit width of sheet, keeping it uniform and as smooth as possible. Do likewise with other three portions of dough, keeping them about 3 inches apart.

Brush top of rolls with beaten egg yolk and bake at 400 degrees for about 20 minutes, or until golden brown and firm to the touch. Do not over bake.

Remove from oven. Let stand covered with a towel for several hours. Then place rolls on a cutting board and slice into 1/2-inch thickness. (Electric knife works very well.) Place on baking sheet with cut sides down and toast at 400 degrees for about 20 minutes, turning them over and around until lightly brown and crisp. Let cool, and store in a closed container.