Pre heat oven to 180°C.
Line a 7 X 11 X 2 inch baking pan with parchment paper. Grease lightly.
In a large bowl, combine the oil, brown sugar, vanilla/white granulated sugar, egg, milk, vanilla and salt. Beat on medium speed for 2-3 minutes or until the sugars have dissolved.
In a separate bowl, combine oats, all flours, baking soda and chocolate chips. Stir until combined. Add to liquid mixture and mix well. Transfer to the preraped tin and spread uniformly. You can bake as is at this point, or spread a 1/4 cup of melted preserves on top with an offset spatula/butter knife and then bake.
Bake 15-20 minutes until golden.Remove from oven and spread the melted chocolate over it and allow to cool until firm.
Once cool, chill for about an hour for the chocolate to set. Cut into bars/ squares and store tightly covered. Refrigerate if the weather is warm because the chocolate will melt. These bars keep well in an airtight box in the fridge for 1-2 weeks.