Slow-Cooker Peanut Butter Chocolate Chip Cake (with regular oven variation)

I have now been without an oven for about 5 days--if confused, read this--and of course all I could think about all day was how much I wanted baked goods.  The second something is impossible is the second it is also really tempting.  After days of wanting homemade bread, complicated meals, and fresh (not frozen) cookies, I decided that I needed to take evasive action. Somewhere I had heard that it was possible to make cake in a slow cooker.  Looking online I couldn't find any recipes that sounded good.  I wanted a really basic cake and I decided peanut butter sounded good, so I figured I might as well give it a shot.  The cake was moist with a good peanut butter taste.  The chocolate and topping really just made a good thing better.  I included directions to make it in an oven as well, for those of you who have one that works.

Serves 6-8

1/3 cup flour
1/2 cup brown sugar
1/3 cup creamy peanut butter
2 tablespoons butter, softened
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2 cups flour
1 1/4 cups brown sugar
2 teaspoons baking powder
1/2 teaspoon baking soda
1/4 teaspoon salt
1/3 cup sour cream
1/2 cup milk
2/3 cup peanut butter
2 eggs
1/4 cup butter, softened
1 cup miniature chocolate chips

1. In small bowl, mix together the 1/3 cup flour and the 1/2 cup brown sugar.  Cut in the 1/3 cup peanut butter and the 2 tablespoons of butter until mixture is crumbly.  Set aside.
2. In mixing bowl, stir together the 2 cups flour and 1 1/4 cups brown sugar.  Add baking powder, soda, and salt.  Stir in sour cream, milk, 2/3 cup peanut butter, eggs, and 1/4 cup butter.  Stir until combined, then beat until light and fluffy.  Stir in chocolate chips.
3. If making in a regular oven, pour mixture into greased 9x13-inch pan.  Top with peanut butter crumbles.  Bake at 375 degrees for 20-30 minutes or until cake tests done.
4. If making in a slow cooker, pour into greased 3-quart slow cooker liner.  Put a double-layer of paper towels and place lid on top.  The towels should stay between the cake and the lid. Cook on high for 90 minutes, then crumble topping over cake.  Reduce heat to low and cook for 30-45 minutes more. 
5. Serve warm or cooled.