I chose this recipe from a recently bought cookbook (1001 Cupcakes, Cookies & Other Tempting Treats - by Susanna Tee), and didn't realise until I had completely filled a 20 x 30cm shallow tin to the brim, just how big it was. For about the first time ever, I cut this bake into more portions than recommended, and still daren't even guess at the calories in each piece. Fortunately, CT was the recipient of 2/3 of the pieces, and we were left with just 4 pieces each, to eat over four days!
The individual layers can just about be seen in the photographs but the whole thing comes together as a sweet, sticky, chewy treat when eaten. Despite the 350g of sugar, a whole tin of condensed milk and 300g of milk chocolate, these squares were not excessively sweet! My only criticism would be not really tasting the peanut butter, but I'm not sure if adding more to the condensed milk would affect how the recipe works.
Base and top layers - rub 225g butter into 350g plain flour and 1 teaspoon of baking powder. Mix in 350g light brown muscovado sugar, 175g rolled oats and 70g chopped nuts (I used almonds, hazelnuts and pistachios). Set aside 1/4 of the mixture and mix an egg into the larger portion (it will still be crumbly). Spread this part of the mixture evenly into a 20 x 30cm x 3cm deep baking tin and press down to bind. Bake at 180C for 15 minutes. Meanwhile mix 300g chopped milk chocolate into the reserved oat and nut mixture.
Middle layer - mix 70g chunky peanut butter into a 400g tin of condensed milk.
When the base is cooked, pour over the condensed milk mix and spread evenly. Sprinkle the reserved crumb and chocolate mix over this, trying to place the chocolate chunks evenly, and press down lightly. Bake for another 20 minutes. Cool completely before cutting into 20 - 24 pieces (leave as long as possible - chocolate stays soft for a surprisingly long time!)