Spinach tomato Ziti

We loved the flavor of the garlic in this dish. I found this in a cookbook (eat, drink and be vegan)but changed it tiny bit.

1 small onion, chopped
6-8 tsp of the minced garlic you find in the jars (or 4 large cloves of garlic minced)
black pepper (freshly ground)
1/4 to 1/2 tsp sea salt
1/3 cup red wine
1 28 ounce can crushed tomatoes (I like Food Lion Brand)
1/2 tsp oregano
1/2 tsp marjoram (I used a bit more since mine was ancient)
1 tsp dried basil
1/2 tsp agave nectar (or sweetener) (OPTIONAL--I like it more tart without it!)
1 pound of penne (used 1/2 regular and 1/2 whole wheat for hubby and GF for me)
1 box of loose fresh spinach (around 6 cups or so)

In my iron skillet (very large one)--saute the onions for 2-3 minutes then add the garlic, the salt, and the pepper and cook for another 6-7 minutes on low heat until the onions are soft---watch carefully so the garlic does not burn. Stir in the wine and let cook for 1 minute. Then add the tomatoes, oregano, marjoram, basil, and nectar. Simmer covered for 15 minutes or longer--if it needs to be thickened you can remove the cover and simmer uncovered for a bit. Add the raw spinach stirring until the heat wilts it. Served over Ziti.