Follow these straightforward instructions to create your Slow Cooker Creamy Tomato Basil Chicken:

1. Prep Chicken: Place the chicken breasts at the bottom of the slow cooker.
2. Add Tomatoes: Pour the crushed tomatoes over the chicken, ensuring the meat is well-covered.
3. Mix Aromatics: In a bowl, combine chopped onions, minced garlic, dried Italian seasoning, salt, and black pepper.
4. Drizzle Olive Oil: Pour the olive oil over the mixture and stir well.
5. Combine Ingredients: Add the aromatic mixture on top of the crushed tomatoes and chicken, spreading it evenly.
6. Cook: Cover the slow cooker and set it to low for 4-6 hours or high for 2-3 hours. Cook until the chicken is tender and cooked through.
7. Add Cream: With the chicken nearly cooked, pour in the heavy cream and chopped fresh basil. Stir gently to combine.
8. Finish Cooking: Let it cook on high for an additional 30 minutes to allow the sauce to thicken and the flavors to meld.
9. Shred Chicken (Optional): For a more rustic presentation, shred the chicken in the sauce with two forks, or leave the breasts whole according to preference.
10. Serve: Once everything is heated through, and the sauce is creamy and aromatic, your dish is ready to be served.

These steps guide you effortlessly through preparing this incredible dish from start to finish!