Preheat the oven to 350℉ (175℃), grease a 9-inch x 3.5-inch (24 cm x 8 cm) Bundt pan with soft butter using a pastry brush and then spray non-stick oil spray all over the pan.
In a bowl, mix the milk and lemon juice; let stand for 5 minutes to create homemade buttermilk.
Add oil, sugar, and vanilla to the buttermilk and whisk until the sugar begins to dissolve and the mixture turns glossy.
Sift flour, cocoa powder, baking powder, baking soda, and salt together to remove lumps and add to the wet mixture in two batches, whisking gently just until the batter becomes smooth avoid over mixing.
Pour in the boiling water or hot brewed coffee, whisking slowly as the cocoa blooms and the batter deepens in color and becomes glossy.
Pour half the chocolate batter into the prepared bundt pan, smoothing it into an even layer.
Add the coffee cheesecake mixture by spoonfuls on top of the first layer, keeping it away from the edges. Add the remaining chocolate batter on top and smooth gently with a spatula.
optional: Use a thin knife or skewer to swirl gently through the layers once or twice, creating a marbled effect without blending the layers together.
Tap the pan lightly on the counter to remove air pockets. Bake at 350°F (175°C) for about 35 minutes or until a skewer inserted into the chocolate portion comes out clean or with moist crumbs.
Cool the cake in the pan for 30 minutes so it firms slightly and pulls away from the sides. Place a serving plate or cake stand over the pan, invert, lift the pan off, and let the cake cool completely.