In a large bowl, combine sugar and oil. Beat together then add cocoa and hot water. Add together until mixed.
Add the eggs and vanilla and mix until combined.
Add flour, baking powder, baking soda, and salt and mix together. Then add sour cream and mix until combined. Do not over-mix.
Fold in the peanut butter chips. Add cup liners to a muffin tin.
Fill the liners evenly with batter, approx. ½ - ⅔ full sprinkle with crumble, then bake 7 minutes at 400°F.
Reduce heat to 350°F and bake 10-12 minutes. Allow to cool completely before serving.