How can I substitute the marmalade?

Thank you so much for your advice, Gammy and Lori T.
It will be raspberry jam or orange marmalade. Both are friends with chocolate

Agree with Lori and might add that raspberry with chocolate is a classic combination.

I don't think there is any reason why you couldn't substitute whatever flavor marmalade, jam or jelly you'd like. It's a flavor combo topping on the brownie, and isn't playing a critical part of the internal structure. If you wanted to stick closer to the recipe flavor profile, a good quality concord grape jelly or jam would work. And I think a nice orange marmalade would be tailor made to succeed.