Angular portal and custom API authentication

Hello all

We have an installation of OIM Version 9.2 and I am working on implementing custom functionality in the angular portal, but I am struggling with authentication.
The custom Endpoint works without any issues, as long as I do not require authentication. I can also call it from the custom angular component I've created.

class CCC_OIM_Batch : IApiProviderFor<PortalApiProject>
    {
        public void Build(IApiBuilder builder)
        {
            builder.AddMethod(Method.Define("ccc/entitlements")
                //.AllowUnauthenticated()
                .Handle<BatchEntitlementsPayload, BatchEntitlementsResponse>("POST",
                    (posted, request) => {
                        return new BatchEntitlementsResponse
                        {
                            Message = "Success"
                    };
                    }
                )
            );
        }
    }
.......

When I uncomment the .AllowUnauthenticated() from the Method definition, it works fine, however when it is in place I get a message that my session expired and that I need to log in.

The user is of course  signed in on the angular portal. How can I pass on the session info from the portal to the API endoint?

Thanks
Martin