Bring a large pot of salted water to a boil. Add fresh green beans and blanch for exactly 4 minutes. Plunge immediately into ice water to lock in bright green color and crisp texture. Drain thoroughly.

In a large skillet, melt butter over medium heat. Add sliced cremini mushrooms and sauté for 5 minutes until browned. Add minced garlic and cook 1 minute.

Sprinkle flour over mushrooms and cook for 2 minutes. Gradually whisk in chicken bone broth followed by heavy cream, Worcestershire sauce, salt, pepper, and nutmeg. Simmer for 3 minutes until thickened into a velvety gravy. Remove from heat and stir in shredded cheddar.

Lightly grease the inside of a 5 to 6-quart slow cooker.

Add blanched green beans, creamy mushroom cheese sauce, and ½ cup of crispy fried onions. Stir gently to coat every bean.

Cover and cook on LOW for 2.5 to 3 hours (or HIGH for 1.5 hours) until bubbling and beans are perfectly tender-crisp. Avoid overcooking to maintain vibrant bite!

Right before serving, scatter the remaining 1 cup of crispy fried onions evenly over the top.

Garnish with freshly chopped parsley and serve warm straight from the slow cooker set to WARM.