Preheat the oven to 425°F.
Spray each ramekin with nonstick spray or olive oil.
Mix 1 tbsp of flour with the unsweetened cocoa powder. Coat the inside of each ramekin and tap off the excess.
In a medium saucepan, melt 1 stick of unsalted butter with the German baking chocolate over very low heat until combined. Remove from heat and let cool.
In a bowl, blend the creamy peanut butter with the powdered sugar and remaining butter until creamy.
In another bowl, beat the granulated sugar, eggs, and kosher salt until thick and pale yellow, about 3 minutes.
Fold in the melted chocolate mixture into the egg mixture until combined.
Fold in the remaining flour and a pinch of salt until smooth.
Spoon two-thirds of the batter into prepared ramekins, add a spoonful of peanut butter mixture, then top with remaining chocolate batter.
Bake for 14 to 16 minutes until the tops are crispy and the centers are jiggly.
Cool for about 10 minutes before inverting onto plates.
Dust with powdered sugar and serve warm.