Buttery pistachio shortbread cookies combine instant pudding mix and chopped pistachios in an easy press-in-pan dough. Cut into squares or triangles for a nutty treat.
Preheat oven to 300˚F. Grease 8 by 8 pan and line with parchment paper.
Cream butter until soft (1 to 2 minutes). Add food coloring if desired. Add pudding mix and sugar and cream together until well combined. Add flour and mix until a dough forms. Add [adjutsable]½[/adjutsable] cup pistachios and mix until just combined.
Press mixture into pan and flatten with an offset spatula (or a measuring cup). Sprinkle with remaining pistachios and press lightly into dough. Score dough into desired number of pieces (16 squares, or 9 squares, and each square in half diagonally).
Bake 30 to 35 minutes. Cool 5 minutes, then cut through (while warm). Allow to cool and remove from pan.
Notes
Keep leftovers at room temperature in an airtight container for up to 7 days and in the freezer for up to 3 months.