Start by mixing together the salt, garlic powder, onion powder and black pepper, then season both sides of the chicken breasts. Heat your skillet over medium‑high, add olive oil and butter, and sear the chicken just enough to get golden brown on both sides (you’re not cooking through at this point).
In a bowl whisk chicken broth and cornstarch until smooth, then pour it into the slow cooker. Add heavy cream (or wait to add later if your slow cooker runs hot), minced garlic, Italian seasoning, salt, black pepper, red pepper flakes and paprika. Place the seared chicken into the crockpot and drizzle the leftover butter/olive oil from the skillet over it.
Top each chicken breast with the chopped sun‑dried tomatoes. Set the slow cooker to low and cook for 6‑8 hours (on the low side) to achieve tender juicy chicken. After cooking, remove the chicken breasts, stir in freshly grated Parmesan into the sauce, return the chicken to the crockpot, spoon the sauce over, add chopped fresh basil, and serve immediately.