Heat olive oil in a Dutch oven or heavy-bottomed pot over medium-high heat.
Pat chicken thighs dry with paper towels (this helps them brown instead of steam).
Season lightly with salt and pepper.
Place chicken in the pot and sear 3–4 minutes per side until lightly golden. Remove and set aside.
Add diced onion and sliced carrot to the same pot.
Sauté for 4–5 minutes, stirring occasionally, until vegetables soften and begin to caramelize.
Add minced garlic and cook 30 seconds until fragrant (don’t let it burn).
Pour in red wine, scraping the bottom of the pot with a wooden spoon to loosen browned bits (that’s flavor!).
Simmer for 2 minutes to reduce slightly.
Stir in chicken stock and thyme.
Return seared chicken thighs to the pot, nestling them into the liquid.
Reduce heat to low, cover, and let simmer for 30–40 minutes.
Chicken should become fork-tender, and sauce will thicken slightly into a glossy glaze. Stir occasionally to prevent sticking.
Remove chicken, shred with two forks, and discard the bones.
Return shredded meat to the pot, mixing with the vegetables and sauce until coated. Taste and adjust seasoning with salt and pepper.
Slice baguette lengthwise, leaving a hinge so it holds together.
(Optional) Lightly toast the inside for extra crunch.
Spoon saucy chicken mixture evenly inside the baguette.
Garnish with fresh parsley or a thin swipe of Dijon mustard for brightness.
Cut sandwich into portions and serve warm, ideally with a glass of the same red wine used for cooking.