Cream butter and sugars until light and fluffy, 5-7 minutes. Add egg and oil, beating well. In another bowl, whisk 2-3/4 cups flour, baking soda, cream of tartar and salt. Gradually beat into creamed mixture, adding flour if needed, until dough forms a ball.
Divide dough into 3 portions. Add red food coloring and vanilla extract to one portion. Add blue food coloring and raspberry extract to the second portion. Add lemon extract to the untinted portion.
Shape each portion into a 10-inch-long block. Place red, white and blue logs side by side. Lightly press blocks together. Wrap and refrigerate until firm, 30 minutes. Unwrap and cut dough crosswise into 1/4-in. slices. Place 1 in. apart on parchment-lined baking sheets. Refrigerate the cookies to set the shape.
To ensure the cookies maintain their shape during baking, begin by removing the tray from the Typhur Dome. Line the bottom of the basket with a layer of aluminum foil, followed by a layer of parchment paper to prevent sticking.
Carefully place the cookies in the cooking tray. Return the tray to the Typhur Dome.
Bake the in "Roast" mode for 10 minutes at 355°F/180℃.
Remove the cookies from the tray.
Try sandwiching two cookies together with a popsicle stick and melted white chocolate or your favorite frosting.