Spinach and Rice Casserole

Lovely comfort food that's not too unhealthy...I'll definitely be making this casserole as a Turkey Day side dish. Great, quick-to-put-together weeknight dish that can be a vegetarian meal in and of itself, or as we served it, with chicken sausages and some sliced tomatoes. This is another casserole that hails from Mollie Katzen's Moosewood Cookbook...a book I've been happily rediscovering of late.
We had brown rice already cooked and in the freezer which made putting this together a snap, but because of that I don't have a firm amount on the rice I used. I think using the recipe as written might end up using a higher ratio of rice to spinach? But heck, it IS a casserole. Just use what looks good to you! :-)
I halved the recipe the recipe as printed in the book because we were eating it as a side dish last night. Had plenty for a nice lunch the next day too. I'm writing up the halved version, so just double and use a 9x13 in. pan if you want more.

Spinach and Rice Casserole:
(Moosewood Cookbook; Mollie Katzen)

1 cup uncooked brown rice (I used a combo of brown and a little red)
1 Tbs olive oil
1 cup onion, chopped
3 cloves garlic, chopped
1 lb fresh spinach, finely chopped (I screwed up and cooked it first, then chopped, but I think that was a less messy way to do it in the end)
1/2 tsp Kosher salt, or to taste
1/4 cup raw sunflower seeds, divided (I questioned the use of these, but they really added a great texture! They also up the protein content if this is your whole meal)
1/8 tsp nutmeg
1/8 tsp cayenne
fresh black pepper to taste
1/2 cup low-fat milk (I used unsweetened soymilk)
1 egg, beaten
3/4 cup grated cheese (I used Cave-aged Gruyere, but recipe suggests cheddar)
paprika
Optional: we enjoyed topping our servings with Cholula hot sauce. :-)

Cook brown rice as per package instructions.
Preheat oven to 350 and butter a 1 quart casserole (I think!...I just used what looked like half of a 9x13).
Heat oil in a deep skillet (I used a Dutch oven) on med-high heat.
Saute onion for about 5-8 minutes until soft; add garlic, spinach and salt and cook about 5 minutes more over medium heat, stirring frequently.
Add to the rice, along with nutmeg, cayenne, black pepper and half (2 TBS) of the sunflower seeds.
Beat together egg and milk and add to the spinach-rice mixture.
Add in cheese and transfer to your buttered casserole dish.
Sprinkle with remaining sunflower seeds and dust with sweet paprika.
Bake uncovered for ~35 minutes, or until heated through and lightly brown on top.