Spinach-Artichoke Dip

My brother was in town last weekend; we went out to dinner and shared a spinach artichoke dip appetizer. (I didn't know he liked it!) With friends coming over for an informal dinner party, I was grocery shopping...artichoke hearts were buy-one-get-one-free at Safeway. :) I thought I'd see if I could mix up a nice homemade dip. The recipe below is a blend of a few I found online: simplified from some of the more time-consuming versions, and with a bit less cheese than many called for! I may tweak it more in the future, but it's really quite tasty.

1/2 oninon finely chopped
6 oz butter
6 oz cream cheese
8 oz sour cream
1 C shredded parmesan
10 oz chopped spinach
1 15 oz jar artichoke hearts, finely chopped/puréed
garlic powder
crumbled bacon
scallions

Sautée onion in butter until very tender. Add the next five ingredients (reserving some of the shredded cheese for topping), successively, blending well after each addition. Add garlic powder to taste. Remove from heat. Put into an oven safe dish; top with remaining shredded cheese. Place in the oven just long enough to melt cheese topping. Garnish with crumbled bacon and thinly sliced green onion (scallions), as desired. Serve with tortilla chips, crackers, pita bread, etc.