Lots of great ways to serve spinach here already. A few more:

• Veggie lasagna. Be sure to wilt and squeeze out excess moisture, otherwise you can end up with a soggy lasagna
• Strata with bacon
• Creamed, and cooked low and slow. Spinach slowly releasing its juices into milk/cream is incredible. Usually with a cheese similar to gruyere or comte. Be sure to grate in some nutmeg. Scratches a similar itch to saag if you want something like that but different
• Florentine anything, but I'm partial to omelettes
• As with most darker leafy greens, added soup or pesto (or if you have a better term for the non-basil family of uncooked smashed leaf/oil/salt/nut or seed/cheese sauces)