Preheat your oven to 350°F (175°C) and grease and flour a 9-inch round cake pan.
Whisk together the dry ingredients in a large mixing bowl: flour, sugar, cocoa powder, baking powder, baking soda, and salt.
Add the wet ingredients to the dry mixture, including softened butter, condensed milk, milk, eggs, and vanilla extract. Mix for 2-3 minutes until smooth.
Pour and spread the batter into the prepared cake pan for an even layer.
Bake in the preheated oven for 30-35 minutes, checking for doneness with a toothpick.
Cool the cake in the pan for about 10 minutes, then transfer to a wire rack to cool completely.
Heat heavy cream in a saucepan until it simmers. Remove from heat and stir in chocolate chips until smooth.
Pour the ganache over the cooled cake, allowing it to drape down the sides.
Slice and serve your chocolate cake with condensed milk. Enjoy!