Preheat oven to 350° F.

Add butter to the bowl of your stand mixer and cream on medium-high for 1-2 minutes, or until butter is smooth and lighter in color.

With the mixer on low, slowly add the sugar and then the egg.

Scrape the bowl with the mixer off.

Turn mixer back on low and add in extracts.

Allow all ingredients to combine fully.

Add the baking powder and then the flour, 1/2 cup at a time, until fully incorporated.

Remove bowl from mixer and drop dough onto a floured countertop. Roll out into a flat disc, about 1/2 inch thick.

Cut cookies into 2-inch, 1 1/2-inch, and 1-inch cookies and bake at 350 for 6-9 minutes.

Let cool on the cookie sheet until firm enough to transfer to a cooling rack.

In a stand mixer with the paddle attachment, cream shortening and butter on medium-high until fully combined and fluffy, about 3 minutes.

Slowly add sugar, one cup at a time. Add meringue powder. (The mixture will appear dry.)

With the mixer on low speed, add lemon juice (or extracts) and salt.

Add in milk. Turn the mixer up to medium-high (or high) and beat until light and fluffy (approximately 5 to 8 minutes).

*You may need to add more milk to reach your desired consistency. Start with the 1/4 cup and if the buttercream is still too dry, add more milk 1 tablespoon at a time until you reach the desired consistency. Make sure the mixer is on low speed when adding in milk and give it at least 30 seconds between each addition.

**You can omit meringue power if you prefer. To achieve the perfect piping consistency, you may need to add more confectioner's sugar