In a roasting pan melt 2 tablespoons of the butter over a moderate heat and cook the shallots until transparent, about 5 minutes. Pour in the white wine and season with salt and pepper. Bring the wine to a simmer and poach the sole fillets for about 8-10 minutes. Transfer the sole fillets to a warmed serving platter. Fold the sole fillets in half and keep warm. Boil the poaching liquid until it reduces by half. In a medium saucepan melt the remaining butter and whisk in the flour. Cook for 2 minutes, stirring constantly. Stir in the crÅme fraöche and boil for 2 minutes. Strain the reduced poaching liquid into the cream mixture and whisk in the tomato paste. Taste for seasoning. Spoon the sauce over the sole fillets before serving.
