Ok... I'm looking for help!

I can't seem to get a straight answer yet, so I'm hoping maybe there will be a baking pro somewhere on the ol BP!
My muffins keep caving in the middle after I bring them out of the oven. It's like deflating tires, but faster. LoL. It only takes them 5 seconds to deflate.
I'm thinking they need more flour, but not sure if I should raise it to 1 1/4 cups, 1 1/2 cups, or 2 cups. If anyone has any tips, secrets, suggestions please let me know. I want to perfecto my muffins.
These are the ingredients:
Pumpkin
Spices
Oil
Flour
Salt
Applesauce
Honey
an egg
Oats
Vanilla Extract
Baking Powder
Baking Soda
Bake at 375 for 15 to 20 minutes.
My second try I left the oats out and did a full can of pumpkin instead of 3/4ths. I also tried half a cup of white flour/half a cup of wheat pastry flour. I was doing 1 cup of wheat pastry flour before. I also increased the honey to 1 cup instead of 1/2 a cup.
Thoughts?