Fudgy Striped Peanut Butter Shortbread

In a large bowl beat butter and peanut butter with a mixer on medium to high 30 seconds. Beat in brown sugar, granulated sugar, cornstarch, vanilla, and salt, scraping bowl as needed. Beat in as much of the flour as you can with the mixer. Stir in any remaining flour. Divide dough into four portions. Cover and chill 30 minutes or until dough is easy to handle.

Preheat oven to 350°F. On a lightly floured surface, roll one portion of dough at a time to 1/4 inch thick. Using a 2 1/2-inch doughnut cutter, cut out dough. Place 1 inch apart on an ungreased cookie sheet. Reroll scraps as needed.

Bake 18 to 20 minutes or until bottoms begin to brown. Cool on cookie sheet 5 minutes. Remove; cool completely on a wire rack. In a small saucepan melt together the chocolate and shortening over medium-low heat, stirring until smooth.

Dip bottoms of cooled cookies halfway in melted chocolate. Place on sheets of parchment paper. Drizzle tops with chocolate. Let stand until set.