Coat the inside of your Crockpot slow cooker with nonstick cooking spray.

Heat olive oil in a small skillet over medium heat. Add chopped onion and cook for 5 minutes until softened.

Add minced garlic to the skillet and cook, stirring constantly, for 1 minute until fragrant.

Transfer the onion and garlic mixture to the prepared slow cooker.

Add the crushed tomatoes, chopped artichoke hearts, pimiento-stuffed olives, and red pepper flakes to the slow cooker. Stir to blend well.

Cover and cook on LOW for 7 to 8 hours or on HIGH for 3 to 4 hours until flavors are melded and bubbly.

About 15 minutes before the sauce is done, cook fettuccine pasta according to package directions until al dente. Drain well.

Divide hot pasta among bowls, top generously with the artichoke sauce, and sprinkle with grated cheese and fresh basil.