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

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

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

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 in 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.

OPTIONAL:

For extra smooth frosting with less air pockets, add buttercream to a food processor 1/2 batch at a time. Process for 3-5 minutes on high, or until frosting appears smooth and creamy like ice cream.

Place directly into piping bags and seal with a rubber band. Can be stored in piping bag until ready to use, up to 3 months.