Preheat the oven to 350 degrees. Line a baking sheet with parchment or foil.
Make the cake by sifting the flour, sugar, cocoa powder, baking powder, and salt into a large bowl. Set aside.
Combine the milk, eggs, melted butter, and vanilla in a small bowl until well combined.
Pour milk mixture into the flour mixture, and beat with a hand mixer (or stand mixer) until smooth & creamy.
Spray 8 baking ramekins with cooking spray and pour the batter into the ramekins, leaving one inch of room from the top. Place on the prepared baking sheet.
Make the self-saucing mixture by combining the boiling water, brown sugar, and cocoa powder until well combined.
Pour ¼ cup onto the top of the cake batter in each ramekin. Side Note: I know it sounds weird, but trust me.
Place in the oven and bake for 25 minutes.
Remove them from the oven and cool.
Meanwhile, make the whipped cream by beating the heavy cream, powdered sugar, and vanilla extract in a bowl with a hand mixer for 3-5 minutes, until fluffy.
Serve the cakes with a dollop of whipped cream. Enjoy.