Red velvet cake bars

Ingredients

1 & 3/4 cups flour (cake or all purpose)

1 cup white sugar

1/2 cup vegetable oil

3/4 cup buttermilk

2 eggs

1 & 1/2 Tbsp cocoa powder

1 Tbsp red food colouring

1 tsp bicarbonate of soda

2 tsp vanilla essence

1 & 1/2 tsp white vinegar

1/2 tsp salt