Birthday Cupcakes

Muffins:

• 2 cups cake flour
• 1 1/2 tsp baking powder
• 3/4 tsp kosher salt
• 1/4 cup Rainbow sprinkles
• 1/2 cup buttermilk
• 1/3 cup grapeseed oil
• 2 tsp vanilla extract clear imitation; regular brown extract is acceptable substitute
• 1 1/4 cup granulated sugar
• 1/3 cup vegetable shortening
• 4 tbsp unsalted butter 1/2 stick, room temperature
• 3 tbsp light brown sugar packed
• 3 large egg

Icing:

• 1/2 cup butter unsalted, 1 stick, room temperature
• 1/4 cup vegetable shortening
• 1/4 cup cream cheese room temperature
• 2 tbsp light corn syrup
• 1 tbsp vanilla extract clear imitation; regular brown extract is acceptable substitute
• 1 1/4 cups powdered sugar aka icing sugar
• 1/2 tsp kosher salt
• 1/4 tsp baking powder
• 1/2 tsp lemon juice fresh
• 2-4 tsp Rainbow sprinkles