Whisk the flour, baking powder, and salt together in one bowl.
Cream the butter and sugar in a separate bowl until the mixture is light and fluffy, about 2 to 3 minutes.
Add the egg and vanilla extract to the creamed mixture and mix until smooth.
Gradually add the dry ingredients to the wet ingredients until the dough forms.
Chill the dough for 1 hour.
Roll the dough out to 1/4 inch thickness, cut your desired shapes, and place them on a lined baking sheet.
Bake at 175°C for 8 to 10 minutes, or until the edges are set but not browned.
Cool the cookies completely.
Prepare the icing by mixing the powdered sugar, meringue powder, and water until the mixture is smooth and glossy.
Divide the icing and color it as desired.
Outline the cookies with icing, then flood the centers. Let the flooded icing dry for 6 to 8 hours.
Pipe the floral details onto the dried cookies using thicker icing.