In a large mixing bowl, combine unsalted butter and granulated sugar. Using an electric hand mixer or stand mixer fitted with a paddle attachment, beat the mixture until it becomes light and fluffy, taking about three minutes. You should see a pale yellow color and a fluffy texture.
Add vanilla extract, almond extract, and kosher salt to the butter-sugar mixture. Beat until well combined. The aroma of the extracts will fill your kitchen, creating a lovely base for your cookies.
Crack the large egg into the bowl and mix until fully incorporated. The mixture should look smooth and creamy, indicating that all ingredients are well combined.
Gradually add the all-purpose flour in about half a cup at a time, mixing slowly to avoid any mess. Once all the flour is mixed in, the dough will begin to come together. Make sure not to overmix; you want a soft and manageable dough.
Form the dough into a ball and divide it into two halves. This makes it easier to roll out later on.
Prepare your work surface by laying down a sheet of parchment paper. Place one half of the dough on the parchment and roll it out to about ¼ inch thick. Try to maintain an even thickness for uniform baking.
Repeat the rolling process with the remaining half of the dough. Place both rolled-out doughs onto large baking sheets and cover them with plastic wrap. Refrigerate for at least two hours or, for best results, overnight. This chilling step helps firm up the dough.
Preheat your oven to 350°F. Line two large baking sheets with parchment paper or a silicone baking mat for easy cleanup.
Select two cookie cutters of the same shape, ensuring that one is slightly smaller than the other, measuring about 2 to 3 inches in size. Use the larger cutter to cut out cookies from the dough. Next, use the smaller cutter to remove the center of each cookie, creating a window for the candy filling.
Place the cut-out cookies on the prepared baking sheet, leaving about an inch or two between each cookie. Repeat the process until you run out of dough, rolling and re-rolling as necessary. If the dough softens, gather it back into a ball and roll it out again. To make handling easier, consider covering the dough and placing it in the freezer for 5 to 10 minutes until firm.
Sort the Jolly Rancher candies by color. Unwrap each candy and place them in separate Ziploc bags. Using a rolling pin, gently crush the candies until they are finely crushed. This will create the stained glass effect.
Spoon a small amount of crushed candies into the center of each cookie cut-out. Be careful not to overfill, as the melted candy will spread slightly while baking. Use about a teaspoon for each cookie, adjusting based on size.
Place the baking sheets in the preheated oven and bake for 12 to 15 minutes, or until the Jolly Rancher candies have completely melted and the edges of the cookies have a light golden color.
Once baked, remove the cookies from the oven and allow them to cool on the baking sheet for about 10 minutes. Then gently transfer them to a wire rack to cool completely before serving.