Sift together corn starch, baking soda, and all-purpose flour in a bowl and set aside.

Cream together butter and sugar until fluffy.

Beat in eggs one at a time until smooth, then scrape the bowl.

Add lime zest, coffee, and vanilla extract and combine well.

Gradually add the flour mixture into the butter mixture using a rubber spatula until a dough forms.

Wrap the dough in plastic wrap and chill in the refrigerator for 30 minutes.

Preheat the oven to 350°F (175°C).

Dust a surface with flour and gently roll the chilled dough into a sheet about 5mm thick.

Cut out shapes using a cookie cutter.

Place the shapes onto a cooking sheet.

Bake for 8-9 minutes, or until the edges are golden.

Add 1 teaspoon of coffee to the dulce de leche and mix well.

Spread the coffee-infused dulce de leche onto half of the cookies.

Cover with the remaining cookies to make sandwiches.

Decorate with coconut flakes, powdered sugar, or crushed candy canes.