Pre-heat the oven to 350 F.

In a saucepan, add butter, vegetable oil and chocolate chips.

Stir over low heat until all of the chocolate chips are melted and the mixture is smooth.

Remove mixture from heat.

Add the sugar and vanilla to the chocolate mixture and stir.

In a mixing bowl, add flour, salt, cocoa powder and shift together.

Add the warm chocolate and butter mixture to the flour along with the eggs and egg yolks.

Blend all those ingredients until it’s smooth.

Grease a 9 X 13 pan.

Bake for ~30-35 minutes.