Begin by placing the cream cheese in the bowl of your crockpot. Set it to high and let it warm for about 5 minutes to soften it up.

After the cream cheese has softened, whisk it until creamy, ensuring no lumps remain.

Add 1/2 cup of heavy cream, the broth, garlic powder, onion powder, salt, and black pepper into the mixture. Stir to combine thoroughly.

Fold in the fresh green beans and sliced mushrooms, ensuring they are well coated with the creamy mixture.

Cover and cook on high for 2 hours or on low for 4 to 6 hours, until the green beans are cooked but still crisp.

While the casserole is cooking, prepare the topping. In a large skillet over medium-high heat, melt 2 tablespoons of butter with the thinly sliced shallots or onions. Cook for about 10 minutes, stirring occasionally, until they become golden brown.

Add the remaining 4 tablespoons of butter to the skillet and continue to cook until it starts to brown, about 2 to 3 minutes.

Remove from heat and stir in the Panko breadcrumbs, crushed cornflakes, smoked paprika, garlic powder, and cayenne pepper. Season with additional salt and pepper to taste.

Once the green beans are done, stir them gently and, if desired, add more cream. Season again with salt and pepper.

Top the casserole with the fried breadcrumb mixture and serve warm.

Alternatively, you can transfer the green beans to a serving dish first and then add the topping.