Cream your butter and sugar together. Stir in the egg and vanilla. Set aside.
In a separate bowl combine the flour and baking powder. Slowly add that to the margarine and sugar mixture.
Combine until the mixture makes a dough. Transfer the to a lightly floured surface. Roll out the dough so it’s about a quarter-inch thick.
Use a cookie cutter to cut out an even number of shapes. As you can see there is extra dough around the edges. Roll out the extra dough and cut it with the same cookie cutter to use it all up.
Place all cookies on a light coloured baking sheet and bake at 400C for about 15 minutes (or until the cookies are golden brown). Cool on the sheet for a couple minutes, then finish cooling them on a cooling rack. Bake one sheet at a time to ensure even baking.
While to cookies are baking, put 1/2 mini marshmallows, 2tsp of light corn syrup, and about 4 drops of food colouring [optional] in a microwave-safe bowl. Microwave on high for 15 seconds and stir. This will be enough filling for about 4 cookies.
Make The Cookies
Place about a teaspoon of marshmallow cream in the centre of one cookie. Spread it out a little bit so that it almost touches the edges. If your cream gets too hard to work with, pop it back into the microwave for about 5 seconds. Its easier to work with if it’s slightly warm.
Add the top and slightly press so the filling goes to the edges. Place on a rack for about 5 minutes to set.