Small-batch Oreo Cupcakes

Ingredients

• 1/8 teaspoon salt
• 1/2 teaspoon baking powder
• 1/4 teaspoon vanilla extract
• 1/4 cup (50g) granulated sugar
• 1 large egg yolk
• 1 1/2 teaspoons vegetable oil
• 2 tablespoons (1oz) unsalted butter
• 1/4 cup (30g) all-purpose flour
• 2 tablespoons (11g) cocoa powder (sifted if lumpy)
• 1 ounce cream cheese (softened)
• 2 tablespoons milk (any percentage)
• 2 tablespoons hot coffee (or water)
• 6 Oreos (divided)
• 2 tablespoons (21g) chopped semi-sweet chocolate (good quality chips are fine)
• 2 tablespoons (1oz) unsalted butter (softened)
• 1 cup (120g) powdered sugar (sifted)
• 1 teaspoon to 1 tablespoon milk or cream
• 3 tablespoons chopped chocolate (good quality chips are fine)