Spray your slow cooker well with non-stick cooking spray.

Blend dry ingredients together (flour, baking powder, baking soda, Allspice, and salt) in a large bowl and set aside.

In a large mixing bowl, beat together the butter and sugar at high speed until light and fluffy, about 3 minutes.

Add eggs to butter and sugar mixture, one at a time, blending after each.

Add in pumpkin and blend well.

Carefully add flour mixture. Turn your mixer down to keep the flour from blowing up as you add it a little bit at a time until it is all added in.

Blend until smooth.

Spread evenly into your prepared crockpot.

Cover and cook on HIGH for about 2-2 1/2 hours. Cooking times may vary depending on your slow cooker.

Toothpick inserted into center should come out clean when your cake is done.

You may wish to line your slow cooker with aluminum foil and then spray. Slow cooker cakes tend to become well done around the edges, the foil may help prevent that.