The way you're doing it is pretty standard. You could switch from an inline sub-query to a Cross/Outer Apply in the From clause, but it won't really do much except change how the query reads.

In your actual query, as opposed to the sample provided, is it actually using table variables, or does it use persisted tables? If so, check the indexing on them. If it's done right, that kind of query can be very fast, unless the amount of data being returned is simply huge.