Choose a cookie dough recipe. Any recipe that creates a cookie that will not spread much or lose its shape is a good choice — I like using my favourite sugar cookie recipe, this blank canvas shortbread recipe, or a gingerbread recipe. Make the shortbread or sugar cookie dough according to the recipe you are using. If the dough is too sticky or tacky at this point, chill the dough in the fridge before rolling it out. Between two sheets of parchment paper or on a well-floured surface, roll out the chilled dough — you want the dough a bit thinner than 1/4-inch in thickness. Keep in mind that each cookie requires you to stack 3 cookies together, so you do not want each cookie to be too thick.
With a cookie cutter of choice, cut out as many cutouts as you can and transfer the cutouts to a large lined baking sheet. With a smaller square cookie cutter, punch out a cut out in the centre of each larger cookie. It is important that you make the smaller square cut out once the larger cut out has been transferred to the cookie sheet, or else the cookie will lose its shape when you try to transfer it. Transfer the baking sheet with the cookie cut-outs to the freezer and chill the cutouts until firm, about 10 minutes. The more chilled the cutouts are, the less likely they will spread or lose their shape in the baking process.
While the cut outs are chilling, gather the smaller cut outs that you have removed from the larger shapes. Re-roll that dough and repeat the previous steps until all the cookie dough has been used up. If the dough starts to get soft, chill the dough again before cutting out the shapes.
Bake the chilled cookie cut outs according to your recipes instructions, until the edges of the cookies are golden. Keep in mind that your cookies will require less baking time than the original cookie recipe because you have a cut out in the centre, allowing the cookie to cook faster. A smaller cookie will require less bake time and a larger cookie with a thicker border will take longer. I recommend checking the cookies at the 5-minute mark. Once the cookies are ready, remove the baking sheet from the oven and allow the cookies to cool completely on the baking sheet before handling. They will be very delicate. Transfer the cookies onto another baking sheet lined/surface with a clean piece of parchment (any crumbs will get 'trapped' inside the isomalt). We will be pouring the isomalt on this surface.
Keep in mind that you will need three cookies per shaker cookie:
1. top cookie which will be filled with isomalt and decorated
2. middle cookie will 'raise' the cookie so the sprinkles can move freely inside the cookie
3. bottom cookie will be filled with isomalt