Making Halloween Cookie Monster Cupcakes is an enjoyable process. Follow these step-by-step instructions to create your masterpiece:

1. Preheat Oven: Start by preheating your oven to 350°F (175°C). Line a muffin tin with cupcake liners.
2. Mix Dry Ingredients: In a large bowl, whisk together all-purpose flour, granulated sugar, cocoa powder, baking powder, baking soda, and salt until well combined.
3. Combine Wet Ingredients: In another bowl, mix the eggs, whole milk, vegetable oil, and vanilla extract. Stir until everything is well incorporated.
4. Combine Mixtures: Pour the wet ingredients into the dry ingredients and mix until smooth. Gradually add the boiling water, mixing until combined. The batter will be thin.
5. Fill Cupcake Liners: Pour the batter into the prepared muffin tin, filling each liner about two-thirds full.
6. Bake: Place the muffin tin into the preheated oven and bake for 20-25 minutes, or until a toothpick inserted into the center comes out clean.
7. Cool: Remove the cupcakes from the oven and allow them to cool in the pan for 5 minutes. Then transfer them to a wire rack to cool completely.
8. Prepare Frosting: In a medium bowl, beat the softened butter until creamy. Gradually add the powdered sugar, mixing well. Add the vanilla extract and heavy cream, then mix until fluffy. Add blue food coloring until the desired shade is reached.
9. Frost Cupcakes: Once the cupcakes are completely cool, use a piping bag to frost the tops generously with the blue buttercream.
10. Decorate: Place a cookie on top of each frosted cupcake to represent the Cookie Monster’s mouth. Add chocolate chip cookies or edible candy eyes as needed to create the character’s eyes.

Now you have created the whimsical and delightful Halloween Cookie Monster Cupcakes!