Cut the chicken into thin strips.
Mix the lemon zest and juice with pepper and thyme. Place the chicken in the mixture and leave for about 15 minutes. Peel the Kohlrabi, quarter and cut into 1/2 cm (approximately 1/8 inch) thin slices. Peel the shallots and finely chop.
Remove the chicken from the marinade, pat dry and cook in hot oil in a skillet over high heat, turning after 3 minutes. Remove from heat, season with salt and keep warm. Add the butter to the pan and sweat the shallots until soft. Add the kohlrabi and sauté for about 3 minutes. Pour in the vegetable broth and let it boil for 5 minutes on medium heat.
Rinse and halve the tomatoes. Stir the creme fraiche into the vegetables and season with salt and pepper. Fold the chicken and tomatoes together and let heat briefly. Finely chop the chicken and place with the vegetables on plates. Optionally, serve with rice.