You could actually use red or yellow peppers for this recipe. It has a wonderful nutty flavour, and is just delicious spread on toast and loaded up with other roast veggies, like aubergines or courgettes.
When you remove the peppers from the oven, cover them with cling film to trap the steam – this makes it easier to then peel them once cool
If you are prone to forgetting that you are toasting nuts and burning them by mistake, you can add the walnuts without toasting them!
You could replace nuts with panko breadcrumbs as an alternative