Preheat your oven to 350°F (175°C) and grease and flour a 9x13 inch baking pan.

In a large bowl, whisk together the flour, cocoa powder, baking soda, salt, and granulated sugar.

Add the eggs, milk, vegetable oil, and vanilla extract to the dry ingredients and mix until well combined.

Carefully stir in the boiling water until the batter is smooth.

Pour the batter into the prepared baking pan and bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean.

Let the cake cool completely in the pan on a wire rack.

In a medium bowl, beat the softened cream cheese until smooth.

Add the creamy peanut butter and mix until well combined.

Gradually beat in the powdered sugar, then add the milk and vanilla extract, mixing until fluffy.

Once the cake is cool, carefully invert it onto a large piece of parchment paper.

Spread an even layer of the peanut butter filling over the entire surface of the cake.

Starting from one of the long sides, carefully roll the cake tightly.

Wrap the roll in plastic wrap and refrigerate for at least 1 hour to set.

In a small saucepan, heat the heavy cream until it just begins to simmer.

Remove from heat and stir in the semisweet chocolate chips until melted and smooth.

Let the ganache cool slightly, then pour it over the chilled chocolate roll.

Refrigerate until the ganache is set, then slice and serve.