Sweet Potato Casserole with Oatmeal Crumble Topping

My boys love yams. I'm posting so it will be handy this week.

6 cups mashed sweet potatoes (that’s about 5 or 6 sweet potatoes depending on how big they are)
3/4 cup brown sugar
1/2 teaspoon cinnamon
1/2 cup heavy cream
1/4 cup melted margarine
1/4 teaspoon salt
2 cups of mini marshmallows (which will be used later)

Preheat the oven to 350 degrees.

At this point your sweet potatoes should still be in the mixing bowl. Add in the brown sugar, the cream, the melted margarine, the cinnamon and salt. Mix well with a hand mixer until everything is mixed in. Then pour the mixture in to an 8 x 8 baking dish and spread it out equally around the dish.

Now make the Oatmeal Crumble.

1/4 cup rolled oats
2 tablespoons dark brown sugar
1 tablespoon all purpose flour
1/8 teaspoon ground cinnamon
2 tablespoons cold margarine

Preheat oven to 375°F.

In a food processor or blender place the oats in and pulse quickly two times; you just want to break them up just a little. Then pour the oats in to a bowl and put in the flour and cinnamon. Cut the butter up in to a few pieces and place in in to the bowl and then cut it into the oat mixture. Meaning take a fork and kind of mash it it to the mixture trying to incorporate it in to as much of the mixture as you can.
Sprinkle the topping over the sweet potatoes as evenly as possible and place the casserole in the oven and bake for about 55 minutes. Keep an eye on it though starting from about the 40 minute marker and the moment the crumble starts to get little brown remove it right away.

Then sprinkle on the two cups of mini marshmallows, cover it with aluminum foil and let it sit for 10 minutes giving the marshmallows a bit of time to melt in a bit