I put this cake in an 11in round tart pan with removable bottom because I didn't have a 9x9 or a bundt. How would you reduce the cook time?

I have a question about step 1 on the recipe "Cranberry Coffee Cake" from aargersi. It says:

"Preheat the oven to 350. Grease and flour a 9x9 pan (I use bakers spray, I am not sure if this is a real baker's no-no but it's a great shortcut!). Roughly chop half the cranberries, leave the other half whole (that sounds funny)"