With a cookie cutter of choice, cut out as many cut outs as you can and transfer the cut outs 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 cut outs until firm, about 10 minutes. The more chilled the cut outs 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
For the isomalt
You will only need two ingredients to cook clear isomalt: isomalt crystals and water. For every cup of isomalt you cook, you will need 1/8 of that amount of water (ex. 1/8 cup of water for every 1 cup of isomalt). The more shaker cookies you are making, the more isomalt you will need. I like to start with at least 1/2 cup of isomalt crystals. You can always make more if you run out while filling your cookies.
Preheat oven to 265F.
Place the isomalt crystals in an oven-safe small pot over medium heat and allow the isomalt crystals to melt without stirring them. Once the isomalt is boiling, remove the small pot from heat. Isomalt will be very bubbly. Hold the small pot off of the heat until the bubbles settle down. Careful to not let the isomalt cook too long on the stove or else it will turn an amber colour like caramel.
Once the bubbles have settled down, place the pot back down on the burner and stir in the water, a little at a time. Steam will aggressively come off of the sugar as the water is now cooling it down. Isomalt will still be very bubbly.
Reduce the amount of air bubbles in the hot isomalt by placing it in the oven at 265F for 8 - 10 minutes. If you skip this step, the bubbles will stay in the isomalt and will harden with the bubbles still visible. After 10 minutes, carefully remove pot of isomalt from oven and use the isomalt while it is still hot. Carefully pour the hot isomalt into the centres of each cookie cut out and spread the isomalt to the edges and corners of each cookie with a small spoon. If the isomalt starts to thicken, place it back in the oven for 2 - 3 minutes, or until it liquefies again. Allow the isomalt to cool completely before moving the filled cookies, at least 10 minutes
Once the isomalt has set, take a piece of paper towel and dab it into a small dish of oil (I use vegetable oil). Gently polish the back side of the isomalt (the side that was on the sheet tray). This will make the isomalt extra see through and remove any cloudiness.
Place one isomalt-filled cookie down. Apply royal icing to the edges of the cookie, being cautious to not get any icing on the 'glass.' Stack the hollow, unfilled cookie before the royal icing dries. Fill your cookie with sprinkles of choice. Create another outline with royal icing. Stack the last isomalt-filled cookie to 'seal' the cookie. Decorate the top of each cookie.
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.
How to make shaker cookies by Amy of Constellation Inspiration