Preheat oven to 350℉/176℃/Gas Mark 4.

In a medium bowl, whisk the all-purpose flour, baking soda, baking powder, salt, and cocoa powder together. Set aside.

In a large bowl, take the softened butter, brown sugar, and granulated sugar and beat on low speed until creamed.

Add the eggs, vanilla extract, red food colouring, and white vinegar to the wet ingredients and continue to beat until all of the ingredients are mixed together or you can no longer see any lumps of butter.

Slowly pour the dry ingredients into the wet, beating on low speed as you add.

When all of the ingredients are fully incorporated together, pour them into either a greased or parchment paper-lined 9x13 pan.

Bake in the oven for 1 hour or until a knife inserted into the centre comes out dry. Let cool while you prepare the cream cheese frosting!

In a medium bowl, beat the softened unsalted butter and whole block of cream cheese until mixed together well.

Add the vanilla extract and salt. Beat again until fully mixed together.

Lastly, sift the icing sugar into the cream cheese frosting, beating the mix on low as you sift.

When fully combined and the mixture is stiff, place into your fridge until the bars are cool enough to frost.