Orange Shortbread with Chocolate Drizzle

1 stick (1/2 cup) butter, softened
1/3 cup cane sugar
1/4 teaspoon vanilla
1 teaspoon finely grated fresh orange zest
1/8 teaspoon salt
1 cup all-purpose flour
1/4 heaping cup dark chocolate chips

1. Heat oven to 375°F. Cream the butter and sugar together in the bowl of a stand mixer using the paddle attachment. Add the vanilla, orange zest, and salt, and combine. Add in the flour and mix until a soft dough forms.
2. Transfer dough to an ungreased 9 x 9 square baking pan and pat evenly over the bottom. Bake for 20 minutes or until the edges are lightly browned. Remove from oven and let cool completely.
3. Melt the chocolate chips in a small glass or ceramic bowl in the microwave. Stir until smooth and drizzle the chocolate over the shortbread. Let chocolate harden before cutting into squares. Makes 9 or 16 squares, depending on how big you cut them.