In a large bowl, combine butter and sugar, then beat at medium speed while scraping the bowl until it becomes creamy. Next, add the egg, lemon zest, and vanilla, continuing to beat until well mixed. Finally, incorporate the flour, baking powder, ginger, and salt, and beat until the mixture is well combined. Refrigerate for at least 1 hour to firm it up.
To get started, preheat the oven to 375°F.
Divide the dough into two parts and roll each on a floured surface to a thickness of 1/8 inch. Use a 3/4-inch heart-shaped cookie cutter to cut out shapes. Place four heart shapes on an ungreased cookie sheet, ensuring their points and sides overlap slightly. Bake for 5-6 minutes until they're set. Allow them to cool completely.
Create a smooth glaze by combining powdered sugar, lemon juice, and red food color in a small bowl. Gradually add water, one teaspoon at a time, until you reach the perfect glazing consistency. Now, take each cooled cookie and generously spread 1/4 to 1/2 teaspoon of this glaze. If you like, use a toothpick to add a touch of yellow food color to the center of each cookie.