Preheat your oven to 350 degrees Fahrenheit (180 degrees Celsius).
In a large bowl, beat butter with sugar until fluffy; beat in eggs, 1 at a time.
Beat in vanilla and chocolate sauce.
Whisk together flour, baking powder, baking soda and salt; stir into butter mixture alternately with sour cream, making 2 additions of dry ingredients and 2 additions of sour cream.
Using a piping bag or ziplock bag with the tip cut off, pipe the batter into the ice cream cones, filling to about 1cm from the top.
Bake in oven until cake tester comes out clean, about 20-25 minutes.
Transfer to rack to let cool.