nigella's breakfast bars - something has gone horribly wrong

[Cappuccino]

ok so I used the recipe here and I substituted banana chips for the nuts as dd1's school has a nut ban

and they burnt. Like, straight away. I thought the oven temp was high so I had it down quite a bit from the recipe but still black in minutes

and it didn't seem like there was enough condensed milk

so now I have some very crumbly falling apart (nice-tasting) oats underneath a crust of black

come on

what went wrong

she also uses a sickening amount of vanilla in recipes. i half it and it's still too much imo.