I found this recipe in a very old American cookbook called Chocolate Lover's Cookies & Brownies which I've had on my bookshelf for donkeys years but never used. I have no idea who Naomi is so any info is very welcome! I had a bit of the oat mixture left so I made them into cookies which worked well.
240g unsalted butter + 2 extra tablespoons
360g soft brown sugar
2 tspns vanilla extract
300g plain flour
1 tspn bicarb of soda
400g rolled oats
200g chocolate (I used Green & Blacks 70% dark)
1 can condensed milk
1. Preheat oven to 160c. Lightly grease a 13 x 9 inch plan.
2. Cream the butter and sugar together in a large bowl. Add the eggs and beat until light. Add vanilla extract.
3. Combine flour and baking soda and stir into the creamed mixture. Blend in the oats.
4. Spread 3/4 of the oat mixture evenly in the prepared pan.
5. Combine the chocolate, condensed milk and 2 tablespoons of butter in a small saucepan. Stir over a low heat until melted. Pour the chocolate mixture evenly over the oat mixture in the tin. Dot with remaining oat mixture.
6. Bake 20-25 mins or until the edges are browned and the centre feels firm. Cool in the pan on a wire rack and then cut into bars.