Preheat oven to 180 degrees C (350 degrees F). Line a muffin tin with paper cases.

In a large mixing bowl combine butter, oil, sugar, flour, baking powder and salt. Beat with an electric mixer at a lower speed until combined. Gradually add milk and beat slowly, until combined. Add eggs, one at a time, ricotta and vanilla, beating at low speed until smooth.

Using an ice cream scoop fill the paper cases ½ full. Bake for about 20 minutes or until the cupcakes are light golden and a toothpick inserted in the centre comes out clean.

Let the cupcakes cool until room temperature before frosting them.

In a large bowl combine butter, cocoa powder and powdered sugar and beat with the mixer at a low speed until combined. The consistency will be sand - like and the butter might not be completely spread: this is ok. Gradually add milk, increasing the speed of the mixer. When the whole milk is absorbed add vanilla extract and beat few minutes at a high speed until light and fluffy.

Use a kitchen knife or a pipe to frost the cupcakes.

Keep them in airtight containers for up to 5 days.