Pumpkin Impossible Pie: "impossible" because it's inedible

For a few years, I've had a found-on-the-Internet recipe called Pumpkin Impossible Pie in my recipe box, waiting for the right time to try it out. I was always a bit curious about Impossible Pie since reading the recipe on the back of the Bisquick box as a kid.
Bisquick Impossible Quiche
Bisquick Impossible Cheeseburger Pie
I may even have eaten one of these before, come to think of it, but I forgot what it was like. My husband met my announcement of the plan for dinner with enthusiasm, declaring he had always liked Impossible Pie when it was served during his childhood.

Being all excited about a crazy new idea for dinner, I didn't follow the recipe exactly and decided to dress it up a bit. When I found the recipe, I was attracted to the idea of a totally vegan, low-fat pie without the hassle of making pie crust on a weeknight. The basics remain the same, but instead of using sugar and pumpkin pie spices, I went for a rosemary-flavored savory pie with caramelized onions and just baked the pie in the skillet I cooked the onions in.

After 60 minutes of baking, the pie had a crust on the outside, was not done at all in the center, and appeared to be underdone on the bottom as well. I used a plate to flip it over so the bottom would be on top and, hopefully, bake more fully.

After 80 minutes of baking and an attempt to remove a piece for eating, here's what it looked like:

The end result? Pie that is about to burn on the outside, but is still undercooked on the inside. Disastrously undercooked. It tasted salty like baking powder and starchy like uncooked flour. The texture was gummy. Additionally, the rosemary was so strong it was astringent and medicinal, and the brown and savory onions had nothing positive to add. To sum up, below is a recipe NOT to follow.

Impossible-to-eat Pumpkin Pie, or How to Ruin the Happy Nostalgia Your Spouse Had for Impossible Pie

2 Tbsp vegan margarine
2 medium-sized onions
pinch salt
1 1/2 c soy milk
1 Tbsp Ener-G egg replacer
1/4 cup water
1 Tbsp cornstarch
2 c pumpkin puree (perhaps my thawed frozen pumpkin puree was part of the problem? it still had a little moisture, which the original recipe recommends against)
1/2 c rice flour
2 tsp baking powder
1/2 tsp salt
1/2 tsp crushed dried rosemary

Preheat oven to 350 degrees Fahrenheit. Melt margarine in 10-inch oven-proof skillet. Slice onions thinly and cook slowly until lightly caramelized and tender. Whisk or blend soy milk with Ener-G, water, cornstarch, then whisk/blend in the rest of the ingredients. Pour pumpkin mix into the skillet with the onions and bake 50 to 80 minutes until top and edges are browned and the center begins to set. Allow to cool, then discard and eat something else for dinner.