Prep the chicken: pat the chicken breasts dry and place each between two pieces of plastic wrap or in a zip bag and gently pound to an even thickness (about 1–1.2 cm). Why: even thickness ensures the breasts cook uniformly — no overcooked edges or undercooked centers.

Make the lemon‑herb marinade: in a shallow bowl whisk together 4 tbsp extra‑virgin olive oil, minced garlic, zest and juice of 2 lemons, chopped thyme/oregano, 1 tsp salt and 4 pinches of black pepper. Why: acid from lemon brightens flavor and the oil carries aromatic compounds and keeps the chicken moist. The garlic and herbs infuse the surface so a short marinade is effective.

Marinate the chicken: add the pounded breasts to the marinade, turning to coat. Cover and refrigerate for at least 30 minutes and up to 2 hours. Why: even 30 minutes will transfer flavor; longer (up to 2 hours) allows more citrus and herb penetration without 'cooking' the meat (no more than 2 hours because lemon juice can begin to firm the surface).

Toast the bread: while the chicken marinates, heat a grill pan or skillet over medium‑high heat. Brush both sides of the sourdough slices lightly with a bit of the reserved olive oil (from the marinade) and toast for 45–75 seconds per side until golden and crisp. Why: toasting creates a flavor contrast and a sturdy surface so the bread won’t go soggy from the slaw and chicken juices.

Make the winter red‑cabbage slaw: in a bowl combine shredded red cabbage and julienned carrot. In a separate small bowl whisk together Greek yogurt, Dijon mustard, apple cider vinegar, 4 tsp extra‑virgin olive oil (for slaw), a pinch of salt and pepper, and the chopped dill or parsley. Toss the slaw with the dressing until evenly coated. Why: the yogurt gives creaminess without heaviness; Dijon and vinegar add tang to cut the richness of chicken and bread. Tossing and resting the slaw for 10–15 minutes softens the cabbage slightly and lets flavors meld.

Preheat grill or grill pan: heat to medium‑high (for a gas grill, around 400–450°F / 200–230°C) so the surface is hot and will sear quickly. Why: a hot griddle creates a golden crust and caramelization which adds flavor while sealing in juices.

Grill the chicken: remove breasts from the marinade and let excess drip off (don’t wipe it all away). Place on the hot grill or pan and cook for about 4–5 minutes per side for 150 g breasts, until well browned and an instant‑read thermometer inserted at the thickest part reads 74°C (165°F). Brush once with a little of the reserved oil while cooking if the surface looks dry. Why: cooking to the correct internal temperature ensures safety and tenderness; quick searing develops flavor through the Maillard reaction.

Rest the chicken: transfer to a cutting board and let rest 5 minutes before slicing. Why: resting allows juices to redistribute so the meat stays moist when sliced.

Assemble the sandwiches: layer two toasted slices of sourdough per sandwich. Spread a little of any remaining yogurt dressing on the bottom slice for extra moisture. Slice each chicken breast and place on the bread, top generously with the red‑cabbage slaw, a sprinkle of extra chopped herbs, a final crack of black pepper, and the top slice of bread. Why: assembling right before serving keeps the bread crisp and the slaw vibrant.

Serve & enjoy: cut each sandwich in half on the diagonal and serve immediately with any extra slaw on the side. Why: the contrast of warm lemon‑herb chicken and cool creamy slaw is most pronounced fresh off the grill.