I am not for sure if it was the sour cream in the batter, but the cake came out soft and moist.  My kids really enjoyed the Crumb Coffeecake.

Crock-Pot Crumb Coffeecake

Crock-Pot Crumb Coffeecake

Ingredients

CRUMB:
2 1/2 Cups All-purpose Flour
1 1/4 Cups Sugar
1/2 Teaspoon Salt
1 1/2 Teaspoons Cinnamon
1/2 Cup Stick Butter, melted
2 Teaspoons Vanilla Extract
CAKE:
1/2 Cup Stick Butter, softened
1 Cup Sugar
2 Eggs
1 Teaspoon Vanilla Extract
1 Cup Sour Cream
2 Cups All-purpose Flour
1/2 Teaspoon Baking Soda
1/2 Teaspoon Salt
1 Teaspoon Baking Powder

Instructions

  1. In a bowl, (crumb mixture), add the flour, sugar, salt and cinnamon and mix.
  2. Add in the stick butter (melted in a microwave) and the vanilla extract.
  3. The crumb mixture will form balls. Mix with a fork until mixture looks mixed well.
  4. Set aside.
  5. In another bowl, (cake portion) add sugar and butter.
  6. Using a electric hand mixer, mix well.
  7. Add eggs one at a time mixing after each one.
  8. Add in the vanilla and sour cream, mix well.
  9. Add in the remaining powder ingredients (all at once) and mix well.
  10. In a well greased baking pan that fits into your crock-pot, add the cake mix.
  11. Then add the crumb mixture evenly over the cake mix.
  12. Cook on HIGH in the crock-pot for 1 hour 30 minutes to 2 hours.
  13. Coffeecake is done once knife comes out clean when stuck in the middle.
  14. Recipe will make 2 Coffeecakes using a bread pan (about 4″ x 9″ ).

http://crockpotladies.com/crockpot-crumb-coffeecake/