Chocolate Chess Pie help

One of the secretaries in my office mentioned yesterday that she was craving pie. And then I talked to my mom about Thanksgiving plans. She's actually taking over hostess duties this year (for the first time), and we were talking about the menu and how I could help. I was delegated bread duty and some sort of chocolate pie duty. Perfect!

I haven't ever made a chocolate chess pie, but I wanted to try it out. Clearly, the answer was to do a dry run of the pie last night and bring it into work, and then, once I proved that it was the most amazing pie ever, use the recipe again for Thanksgiving dinner. Perfect, right?

Only, the pie is not perfect. The crust is (it's Dorie's perfect crust). But the filling ... some thing's not right. It doesn't seem done. Here's the recipe I used from about.com (which I should have known better than to trust), chosen largely because I had all of these ingredients already:

Ingredients:
1/4 cup butter
1 1/2 ounces unsweetened chocolate
1 1/2 cups sugar
1 tablespoon flour
pinch of salt
1/2 cup milk
2 eggs
1 teaspoon vanilla extract
1 unbaked 9" pastry shell

Preparation:

Melt butter with chocolate.

In a mixing bowl, combine chocolate and butter mixture with sugar, flour, salt, milk, eggs, and vanilla; beat with electric mixer for 5 to 6 minutes.

Pour filling into prepared pastry shell; bake at 350° for 35 to 45 minutes, until set.

And that's what I did! I checked it at 35 minutes, and it didn't look done, so I left it for the last 10 minutes. I assumed that it must be done - I don't do a lot of pie, so I wasn't sure how to tell if it was set. The top is solid, and even cracked, but the inside just isn't quite set, especially at the center of the pie.

Do you have a no-fail chocolate chess pie recipe? Did I do something wrong with this one?