Instructions

• Preheat your oven to 350 degrees Fahrenheit or 175 degrees Celsius so it’s ready when you are.
• Sift together flour, baking powder, and salt in a large bowl.
• Using an electric mixer, beat butter until light and fluffy, about 3 minutes. Add in sugar and beat an additional 2 minutes more.
• Add eggs, one at a time, beating after each addition, followed by the vanilla extract.
• Add the flour mixture and beat on low until just combined.
• Divide the dough in half. Form half of the dough into a 4 by 4-inch square, wrap in plastic wrap, and set aside.
• Return the other half of the dough to the mixing bowl. Melt the chocolate using a double boiler or microwave. Mix melted chocolate into the dough just until combined.
• Form the chocolate dough into a 4 by 4-inch square, wrap in plastic wrap, and place both chocolate and vanilla doughs into the refrigerator for 30 minutes (or up to 3 days).
• Cut each dough into four even strips. Roll out one strip of vanilla dough and one strip of chocolate dough between parchment paper into roughly 6-by-7 inch rectangles.
• Flip the vanilla dough over onto the chocolate dough. Trim excess dough into a rectangle and lightly press together. Roll the dough into a log, wrap in plastic wrap and refrigerate. Repeat for all strips to form 4 logs.
• Refrigerate logs for 1 hour, roll each log several times to prevent flattening, then transfer to freezer for 2 hours or up to 3 months.
• Preheat oven to 350 °F and line a baking sheet with parchment paper.
• Slice frozen dough into ¼-inch thick slices and place 1 ½ inches apart on baking sheet.
• Bake 9 to 11 minutes until vanilla dough is slightly golden. Cool on wire rack.