Filling
2/3 cup sugar
1/3 cup cocoa powder
2/3 cup milk
1 tsp vanilla
1/2 cup peanut butter
For the filling, mix sugar and cocoa in a small saucepan. Gradually stir in milk. Cook until boiling.
Remove from heat. Stir in peanut butter and vanilla. Set aside.
Streusel
1/2 c brown sugar
1/2 c flour
1/4 c butter
1/4 c peanut butter
Mix sugar and flour. Cut in butter and peanut butter. Set aside.
Banana Batter
1 c sugar
1/4 c butter
3/4 tsp baking soda
1 tsp kosher salt
2 eggs
1 tsp vanilla
3 medium bananas
2 c flour
Cream sugar with butter, soda, and salt, using a mixer. Beat in eggs and vanilla, adding one at a time. Mix in bananas. Stir in flour.
2 or 3 bananas sliced thinly lengthwise
In a buttered 9"x5" pan, pour half of banana batter. Pour over half of chocolate filling. Top with other half of batter. Then top with remaining chocolate filling. Draw a knife through to swirl. Cover top with sliced bananas. Top with streusel. Bake at 350F for 75 minutes.