Whisk together the flour, baking powder and salt and set aside.
Cream together the butter and ¾ cup sugar with an electric mixer. Add the corn syrup, egg and vanilla and mix well. Gradually add the flour mixture, with the mixer on low, and beat until combined. With a spatula, scrape the sides and bottom of the bowl to make sure everything is mixed well.
Roll the dough into 1-inch balls then roll in the sanding sugar and place on a plate or baking sheet – you can put them on top of each other – and refrigerate for 30 minutes. You can make ahead of time but if they are refrigerated for more than 30 minutes you will have to let them sit out for a few minutes before proceeding.
Preheat oven to 350 degrees. Line 2 cookie sheets with parchment paper or silicone baking mats.
Place the balls on the prepared cookie sheets about an inch apart. Flatten with your thumb, making an indentation in each ball. Bake for 10-12 minutes or until firm but not beginning to brown. Leave oven on. If the indentations have risen, use the end of a wooden spoon to depress again. Fill each indentation with a teaspoon of chocolate chips. Return to oven for 2 minutes. Using a small offset spatula or spoon, swirl the chocolate chips to melt. Top each cookie with a maraschino cherry half.