Preheat the oven to 325°F (163°C).
Grease and flour a bundt pan evenly.
In a large bowl, beat butter and sugar together.
Add eggs one by one, beating after each addition.
In another bowl, whisk flour, baking powder, and salt.
Add dry mixture to butter mixture, alternating with milk.
Stir in Hennessy Cognac and vanilla extract.
Pour batter into the greased bundt pan.
Bake for 1 hour and 15 minutes or until done.
Cool the cake in the pan for 10 minutes.
Transfer cake to a rack and cool completely.