Preheat an oven to 350⁰F.

Line baking sheets with parchment paper.

Add butter and sugar to a large mixing bowl and mix until light and fluffy and sugar crystals begin to dissolve.

With the mixer running at low-speed sprinkle in the baking powder and mix until well incorporated.

Add the eggs one at a time mixing well between each addition.

Add the vanilla.

Turn off the mixer and add half of the flour. Using low-speed mix just until the flour isn’t flying everywhere.

Turn off the mixer and add the last half of the flour. Using medium speed, mix just until the flour is all incorporated. Do not overmix.

Flour a working surface and place 1/3 to 1/2 of the dough mixture onto the working surface.

Pat the dough into a thick circle.

Using a rolling pin, roll the dough out to a thickness of 1/4 to 1/3-inch.

Cook cookies into desired shapes and place onto prepared baking sheets.

Place cookies into the preheated 350⁰F oven and bake for 8 to 9 minutes or until the cookies no longer wet in the middle.

Remove the cookies from the oven and allow to cool on the cookie sheet for at least 10 minutes.

Move the cookies to a cooling rack to allow them to cool completely before icing.

Add all ingredients to a mixing bowl and mix on low to medium speed until peaks being to form 7 to 10 minutes.

Once mixed, keep icing covered, removing only what is needed at a time to prevent royal icing from crusting or hardening.

Thin out royal icing with additional water to achieve a toothpaste consistency for outlining and a shampoo consistency for flooding using small amounts of water. Do not use a mixer for thinning out the icing.