Preheat oven to 350 degree Fahrenheit.
Prepare two 8 inch cake pans or one 12 inch cake pan with parchment paper in the bottom or grease the bottom with butter and then grease the side.
Mix the dry ingredients together flour, pudding mix, salt, baking powder in a bowl and set aside.
In a big bowl add butter,brown sugar and vegetable oil beat together well for about 3 -4 minutes until fluffy and light in color.Don't reduce the creaming time.
In the same bowl add eggs ,vanilla extract and mix until smooth and combined well.
Now add half of the dry ingredients and mix until well combined .Keep scrape down the sides of the bowl to add all the all extra flour.
Add milk and mix until well combined then add the remaining dry ingredients and mix until combined well.
Divide the batter into equal parts if you are using 2 to 3 pans or pour directly into single pan and bake for 25 to 30 minutes, then remove to cooling racks to cool completely.