I don't have orange marmalade and don't want to buy a whole jar of it. Would omitting it in this recipe make a big difference or can I just add mo...

I've made this. I also didn't want to buy marmalade. I used orange zest and a little reduced juice with golden syrup added. It was delicious, but I can see where the marmalade would add a certain something. I still wouldn't buy any because I don't eat toast and I rarely make recipes that call for it.

I'd guess that the marmalade isn't there to add sweetness but to deepen the orange flavour and add some fabulous bitter notes to the dish, creating a more complex taste. Assuming that the marmalade required is decent marmalade, and not just a vaguely orange sugar spread that is.

Zest might replace that but it's not been through the cooking process so the flavour is different, honey probably won't replace it just make it sweeter. So go get some good marmalade. A whole jar doesn't take up much space, it's a preserve so it's going to last and it tastes awesome. On toast, on crumpets, on scones. I heartily endorse the making, purchase and use of marmalade. It's an autumnal breakfast hug in a jar.

Orange marmalade is not as sweet as honey. I would add a little more honey (like a tsp or two) and some orange zest if you have it.

I'm not the author of the recipe, but I would say, yes, add the extra honey. It's a tablespoon, so it's not the major flavor ingredient in the sauce. If you have an orange or tangerine laying around, you can also add some of the zest and give a similar effect that the marmalade would give.