I get creative with this recipe and make the colors of the stripes according to the season/holiday. The recipe colors as written are "Christmasy". Prep time does NOT include time for dough to chill.
Line a 9x5x3-inch loaf pan with wax paper or parchment paper (try to get most wrinkles out); set aside.
Cream together butter and sugar in a large mixing bowl; beat in egg.
In a separate bowl, combine flour, baking powder, and salt; gradually beat this into creamed mixture.
Divide the dough into thirds; each in it's own small bowl.
Add crushed mints and red food color to 1 third; mix well (may need to use hands to blend color well).
Add melted chocolate to another third; mix well (may need to use hands).
Add nonpareils and green food color to last third; mix well (may need to use hands).
Spread red dough on bottom of lined loaf pan. Spread chocolate dough on top of that. Lastly, spread the green dough on top. Cover with plastic wrap and chill for at least 2 hours (or place in freezer for 1 hour).
When chilled and firm, remove dough from pan.
Preheat oven to 375°F.
Lay the loaf of dough flat on a cutting board (just the way it was in the loaf pan) and use a large knife to cut dough down the middle lengthwise. Now cut each strip into 1/4" - 1/2" slices across (so each is "striped).
Place slices 1" apart on lightly greased baking sheets. Bake at 375°F for 10-12 minutes or until edges just begin to brown.