The casing was a built-up treatment using several custom molding profiles.
I made the steps in three successive passes on my table saw.
I used a dado head in the table saw to relieve the back of the casing.
The carpenter who installed the original casing used a jack miter, a combination of a butt joint and a miter, to join the stepped casing stock.
A power miter saw actually adds a step, since you still have to use a hand saw to finish the inside shoulder cut.
The jig holds the casing on edge with only the profiled, mitered portion exposed.
I used a Jorgensen "mini-precision" miter saw mounted on a 45-degree angle block.
I used Titebond's Molding and Trim glue along with pocket-hole screws to hold the joints together.
I produced the profile for the two-piece backband on the router table, first hogging off the waste wood on the table saw.
The backband turns vertically across the head casing for a slightly wider reveal.
A flat, nominal 1x2 cap with a coved edge detail finishes off the crown.
The finished molding