Preheat the oven to 350°F (177°C) and line a cupcake pan with paper liners or lightly grease with butter and flour.

In a medium mixing bowl, whisk together the flour, baking powder, baking soda, salt, cinnamon, nutmeg, espresso powder, and sugar until fully combined.

In a large separate bowl, vigorously whisk the vegetable oil, milk, strong brewed coffee, eggs, and vanilla extract until smooth and cohesive.

Gradually incorporate the dry ingredients into the wet ingredients, stirring gently until just combined. Take care not to overmix to maintain a light texture.

Divide the batter evenly among the prepared cupcake liners, filling each about two-thirds full. Depending on the size of your liners, you may need to bake in batches.

Bake for 25–30 minutes or until a toothpick inserted into the center comes out clean. Allow the cupcakes to cool in the pan briefly before transferring them to a wire rack to cool completely.

For the buttercream, beat the softened butter on medium speed until light and fluffy, about 3–4 minutes.

Gradually add the sifted powdered sugar and salt, beating on low speed initially to prevent a sugar cloud, then increasing to medium-high until smooth.

In a small bowl, whisk together the heavy cream, brewed coffee, instant espresso powder, and cocoa powder until the mixture is smooth. Slowly stream this mixture into the frosting while beating, stopping once the desired consistency is reached. You may not need all the liquid depending on your preferred frosting texture.

Frost the cooled cupcakes generously, using a piping bag or a spatula, and finish with a light dusting of cocoa powder for an elegant touch. Enjoy the rich coffee flavor and creamy mocha frosting with every bite.