Bittman's quiche cooking time & temp?

So this is the 2nd time I have made a doctored version of the How to Cook Everything quiche... and it takes nearly forever to cook! The recipe calls for baking at 325 degrees for 30-40 minutes. After 40 minutes (with no peeking & a completely preheated oven), the quiche was still liquid. Not anywhere near set. So I baked it 15 minutes more... and still more runny than my toddlers' noses during the 6 month winter. After another 10 minutes, still not near set. So after 65 minutes, I bumped the heat to 350 & gave it another 10 minutes. And did I mention it's almost 11:30 and I am ready for bed?

Is there something I'm missing? I did doctor it with caramelized onions, a little garlic, sauteed mushrooms & a handful of spinach to go along with the 6 eggs & scant 2 cups of cream. I know it will be super yummy, but 75 minutes? I know my oven is good... perhaps I should use the convection i/o regular bake? Anyone have a secret so when I try it again I won't be this annoyed? Thankfully, this was not planned for tonight's dinner.