Spray the interior of the slow cooker with cooking spray, or use a plastic liner.

Place chicken thighs in the bottom of the slow cooker and sprinkle with Italian seasoning, red pepper flakes, salt, and black pepper.

Evenly layer sun-dried tomatoes and sliced olives over the seasoned chicken.

Heat olive oil in a saucepan over medium heat. Add onion to the hot oil and cook until onions begin to get tender, 3 to 4 minutes. Add garlic and cook until fragrant, about 1 minute.

Using a slotted spoon, transfer onions to the slow cooker and spread evenly over the sun-dried tomatoes.

Return the skillet to medium heat and add cream, stirring until all the olive oil is incorporated and the sauce begins to bubble. Pour cream sauce evenly over the onions.

Cover slow cooker and cook on High for 3 to 4 hours or Low for 6 to 7 hours if you prefer a longer cook time.

Remove cooked chicken and vegetables to a serving platter. Add torn spinach to the sauce and cook until wilted, 3 to 5 minutes.

The sauce will be a bit thin. If you like a thicker sauce, pour into a small saucepan over medium heat. Combine 2 tablespoons cornstarch and 2 tablespoons water to form a slurry. Stir constantly until bubbly and thickened, 5 to 7 minutes.