Step 1: Season the Chicken - Pat the chicken thighs dry with paper towels, especially on the skin side. This little step helps the chicken brown better in the skillet, and it keeps the seasoning from sliding right off. Sprinkle both sides of the chicken with 1 teaspoon of the Italian seasoning, salt, and black pepper. I like to press the seasoning in gently with my hands so every thigh gets an even coating.
Step 2: Heat the Butter for Searing - Set a large skillet over medium high heat and add the butter. Let it melt and start to foam, but keep an eye on it so it does not burn. You want the skillet hot enough that the chicken gives you a good sizzle the moment it touches the pan. That sound is your dinner getting a head start.
Step 3: Sear the Chicken in Batches - Place the chicken thighs skin side down in the hot skillet, working in batches so you do not crowd the pan. Let them cook for 3 to 4 minutes on each side, until they have a deep golden color. You are not trying to cook them all the way through here. You are simply building flavor and giving the finished meal that rich, roasted chicken look that makes everyone think you worked much harder than you did.
Step 4: Build the Garlic Potato Base - Add the red potatoes to your slow cooker. Drizzle them with the olive oil, then add the minced garlic, the remaining teaspoon of Italian seasoning, salt, and black pepper. Stir everything together until the potatoes are lightly coated, then spread them into an even layer across the bottom. Try to keep the potato pieces about the same size so they finish cooking at the same time.
Step 5: Nestle the Chicken Over the Potatoes - Place the seared chicken thighs on top of the potatoes, skin side up. Keeping the skin facing up helps it stay as appealing as possible while the chicken cooks. The potatoes underneath are about to become something special because they will soak up the butter, chicken juices, garlic, and seasoning as everything cooks together.
Step 6: Slow Cook Until Tender - Cover the slow cooker and cook on high for 3 to 4 hours or on low for 6 to 8 hours. The chicken is done when it reaches between 175 and 195 degrees Fahrenheit in the thickest part of the thigh, away from the bone. Chicken thighs are forgiving, which is one reason I love them for slow cooker dinners. They stay tender and juicy even after a long cook, and the meat should pull easily from the bone.
Step 7: Finish With Parmesan and Parsley - Once the chicken and potatoes are cooked through, sprinkle the freshly grated Parmesan over the top while everything is still hot. Let it sit for a few minutes so the cheese softens and settles into all those warm nooks and crannies. Finish with chopped parsley, then bring the slow cooker right to the table or transfer everything to a big serving platter.