Heat a large pan to medium-high. Add 30g clarified butter. Once hot, fry chicken strips 2-3 minutes until starting to brown.
Add 2 peeled and diced onions to the pan with the chicken. Fry over medium heat 3-4 minutes, stirring, until onions are translucent. Season with salt and pepper.
Sprinkle 2 tablespoons flour over the chicken and onions. Stir constantly 1-2 minutes until the flour is absorbed.
Stir in 2 tablespoons tomato paste and mix well for about 1 minute.
Pour in 250 ml vegetable stock. Bring to a simmer over medium heat and simmer 5 minutes until chicken is cooked through (internal temperature 74°C/165°F) and sauce thickens slightly.
Remove from heat. Stir in 200g crème fraîche until well combined. Add 2 teaspoons green pepper from the glass and gently stir. Return to medium heat and warm through without boiling vigorously.
Meanwhile, cook 400g green ribbon pasta in boiling salted water according to package directions. Drain well.
Divide pasta among serving plates, pour chicken and pepper sauce over top, and garnish with 1 bunch chives cut into thin pieces.