Preheat oven to 350°F.
Line cookie sheets with parchment paper or lightly grease and dust with flour.
Cream butter and sugar in large bowl until blended.
Add almond paste and egg yolk; beat until light.
Blend in flour to make a smooth dough.
Turn out onto lightly floured board.
Divide into 8 equal pieces; divide each piece in half.
Roll each half into a 12-inch rope; cut each rope into 2-inch lengths.
Place 2 inches apart on prepared cookie sheets.
Bake 10 to 12 minutes or until edges just begin to brown.
Remove to wire racks to cool.
Melt chocolate chips in small bowl over hot water.
Stir until smooth.
Dip both ends of cookies about 1/2 inch into melted chocolate, then dip the chocolate ends into pistachios.
Place on waxed paper; let stand until chocolate is set.