In a large bowl, cream together: butter, granulated sugar and brown sugar. Beat until light and fluffy (about 2–3 minutes). Add: oil, 2 large eggs (one at a time), 1½ tsp vanilla and beat until well combined. Alternatively, add dry ingredients and milk:
Add ½ of the flour mix and stir gently, then add all the milk and stir it gently. Add remaining flour and mix just until combined, then pour in ¼ cup hot coffee (or hot water). This thins the batter and “blooms” the cocoa. Mix until smooth.
Batter will be pourable and fill cupcake liners ¾ full. Bake for 18–20 minutes, or until a toothpick comes out with a few moist crumbs. Let cupcakes cool in the pan 5 minutes, then transfer to a wire rack to cool completely.
Once cupcakes are completely cool, use an apple corer or small knife to remove a 1-inch core from the centre of each cupcake. Fill each hole with 1 to 1½ teaspoons of caramel sauce. For extra gooeyness, slightly warm the caramel first.
Optionally, replace a small piece of the removed cake as a cap. To make the caramel nuttercream, beat ½ cup softened butter for 2–3 minutes until pale and creamy. Gradually sift in 1¾ cups powdered sugar, beating well after each addition.
Add ¼ cup cooled caramel sauce and beat for 1–2 more minutes until fluffy and smooth. If too thin: Add a bit more powdered sugar. If too thick: Add 1 tsp milk or cream. Optional: Add a pinch of salt for a salted caramel twist.
Use a piping bag with a large tip or a butter knife to frost each cupcake generously. Warm leftover caramel slightly and drizzle over the top of each cupcake.
