Peel and dice the onions. Rinse the chicken breast fillets with cold water, dry them and dice them very finely.
Score the tomatoes and briefly put them in hot water. Lift out, peel, then roughly dice. Wash the basil and shake well dry, then set aside a few leaves for garnish. Cut the rest into fine strips.
Heat the (preferably) wok and then the oil in it. Let the onions become translucent while stirring. Gradually add the chicken, stir-fry for about 1 minute and move to the edge. Then put the chopped tomatoes and the creme fraiche in the wok. Mix all ingredients together, season with the finely chopped basil, salt and pepper. Simmer for about 4 minutes while stirring over high heat. Season the sauce with salt and pepper and serve garnished with the basil leaves.