Preheat oven to 350 degrees. Line the cupcake pan with paper liners.

Using a medium bowl, whisk flour, baking powder, salt, and baking soda.

In a separate mixing bowl, beat butter with an electric mixer on medium high for 30 seconds.

Add eggs one at a time, beating well after each addition.

Alternate the flour mixture and almond milk to butter mixture, beating on low speed until everything is well mixed together.

Fill the cupcake liners 3/4 full with cake batter.

Bake at 350 degrees for 20–25 minutes.

Allow to cool in the cupcake pan for 10 minutes.

Remove cupcakes from pan and allow to cool completely on wire rack.

Cream the butter and powder sugar until it looks light and creamy.

Stir to mix well.

If it doesn't cream, add several drops of the heavy whipping cream until it creams.

Test to see if the frosting can form and hold a stiff peak by taking a spoonful of frosting and turning the spoon upside down. If the frosting stays on the spoon, it is ready; if not, then...

Add more powder sugar, 1/2 cup at a time.

Mix well.

Test to make sure that the frosting can make and hold a stiff peak.

If ready, scoop the frosting into a pastry bag with a star tip.

Twist the open end of the pastry bag to push the frosting to the tip.

Start by frosting on the outside edge of the cupcake, working to the center of the cupcake.

Place a shelled pistachio in the center of the frosted cupcake.