Ease of preparation
- 1 ¼ cups (300 ml) butter
- 1 cup (240 ml) shortening
- ½ cup (120 ml) sugar
- ½ cup (120 ml) icing sugar
- 1 egg, whisked
- 1 teaspoon (5 ml) vanilla
- 2 ¾ cups (660 ml) flour
- ½ tablespoon (7.5 ml) baking powder
- ½ teaspoon (2.5 ml) baking soda
- ½ teaspoon (2.5 ml) salt
- 4 gel food colourings: black, blue, pink, purple
- 3 natural food extracts: blueberry, strawberry, banana
- Silver glitter dust, to decorate
- Preheat oven to 350 F (175 F).
- Using a hand mixer, cream butter and shortening with sugar and icing sugar in a bowl. Add egg and vanilla and continue beating at medium speed until thoroughly combined.
- In a separate bowl, whisk together flour, baking powder, baking soda, and salt. Gradually add flour mixture to the butter mixture and continue blending on low speed until thoroughly combined.
- Divide dough in half.
- To the first half, add black and blue gel food dye and blueberry extract and stir until thoroughly combined.
- Divide second half of dough into 3 smaller bowls:
- To one small bowl, add pink food colouring and strawberry extract and stir until thoroughly combined.
- To the second small bowl, add purple food colouring only and stir until thoroughly combined.
- To the third small bowl, add banana flavour extract only and stir until thoroughly combined.
- Refrigerate all doughs for 2 hours.
- Turn the dark blue dough onto a large piece of parchment paper. Place a second piece of parchment paper on top. Roll dark blue dough into a large rectangle of 1/8-inch (3mm) thickness. Set the blue dough rectangle aside.
- Knead each of the pink, purple, and plain doughs separately on a generously-floured surface. Roll each dough into equal size long fat ropes.
- Lay all three ropes lengthwise beside each other on a large piece of parchment paper. Place a large piece of parchment paper on top and roll out into a large rainbow rectangle of 1/8-inch (3 mm) thickness.
- Remove the parchment paper from the top of the dark blue rectangle. Place the rainbow rectangle on top of the dark blue rectangle. Carefully roll into a large log. Cover the log with parchment paper, shaping and smoothing to remove air bubbles.
- Refrigerate for at least 2 hours.
- Slice log into ¼- to 1/3-inch (3-8 mm) slices and bake for 12-15 minutes at 325 F (160 C).
- Sprinkle with silver glitter dust. Cool on baking sheet for one minute before transferring to a wire rack to cool completely.