Heat the oil and the butter together over medium heat. Add the peppers, onions and a good pinch of salt. Fry for 5 or so minutes or until translucent (no colour). Add the garlic, fry briefly, then add the seasoning and flour. Cook out briefly, then add the water. Bring to a simmer then add the chicken and sour cream. Stir to combine.
Add the chicken stock pot and melt into the sauce. Remove from the heat and add to your 4 empty mugs. Brush the tops of the mugs with egg wash then top with circles of pastry that are 1 cm wider than your mugs.
Bake for 25 minutes at 190°C, or until nicely coloured, crisp and risen.