For the Cookies:

1. Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper or a silicone baking mat.

2. In a large bowl, cream together the softened butter and sugar until light and fluffy, about 2-3 minutes.

3. Add the eggs, one at a time, and mix well after each addition. Stir in the vanilla extract.

4. In a separate bowl, whisk together the flour, baking soda, salt, and cocoa powder.

5. Gradually add the dry ingredients to the wet ingredients, alternating with milk. Start with the dry ingredients, add half of the milk, then the rest of the dry ingredients, and finally the remaining milk. Stir until just combined.

6. Stir in the boiling water to thin the batter. It will be quite thin, but that’s okay!

7. Drop spoonfuls of dough (about 1 tablespoon each) onto the prepared baking sheet, spacing them about 2 inches apart.

8. Bake for 8-10 minutes or until a toothpick inserted into the center of a cookie comes out clean. Remove from the oven and let the cookies cool completely on the baking sheet.

For the Fudgy Icing:

1. In a medium saucepan, melt the butter over medium heat. Stir in the cocoa powder and milk, and bring to a simmer, stirring constantly.

2. Once the mixture comes to a simmer, remove it from the heat and stir in the vanilla extract.

3. Gradually add the powdered sugar, stirring until smooth and well combined.

4. Pour the warm icing over the cooled cookies, spreading it evenly with a spatula.

5. If desired, sprinkle chopped walnuts or pecans on top for added crunch and flavor.