Wash the green beans well. Trim the ends carefully. Cut large beans into smaller pieces for easier eating.

Fill a large pot with water. Add green beans and cook for five minutes until slightly tender but still bright.

Pour the green beans into a colander. Rinse with cold water immediately to stop the cooking process completely.

Place butter in a skillet over medium heat. Add chopped onions and cook until soft and lightly golden.

Put sliced mushrooms into the skillet. Stir often until mushrooms become soft and release their natural moisture.

Mix minced garlic into the skillet. Cook for one minute until fragrant and flavorful without burning the garlic.

Sprinkle flour over the vegetables. Stir slowly until combined. Cook for one minute to remove raw flour taste.

Pour chicken broth and heavy cream into the skillet. Stir constantly until the sauce becomes smooth and creamy.

Add salt, black pepper and paprika. Mix everything well so every spoonful tastes flavorful and balanced.

Stir shredded cheddar cheese into the sauce. Continue mixing until cheese melts completely into the creamy mixture.

Place green beans into the skillet. Mix carefully so every bean gets coated with the creamy mushroom sauce.

Grease a baking dish lightly with butter or cooking spray. This helps prevent sticking during baking time.

Pour the green bean mixture into the baking dish evenly. Spread it gently with a spoon for even cooking.

Sprinkle crispy fried onions over the casserole. Cover the top evenly for a crunchy and delicious finish.

Bake at 375°F for 25 minutes. The casserole should bubble around the edges and look golden on top.

Remove casserole from the oven carefully. Let it rest for five minutes before serving to thicken slightly.