Sauté the Vegetables

In a large skillet over medium-high heat, melt the butter. Add the chopped onion and lightly season with salt. Cook until softened and translucent, approximately 5 minutes. Stir in the celery and garlic, cooking until aromatic and tender, about 2 minutes. Transfer the mixture to a slow cooker (6- to 8-quart capacity).

Prepare the Chicken and Broth

Place the chicken thighs in the slow cooker, followed by the chicken stock, white wine, and lemon juice. Season with red pepper flakes, a teaspoon of salt, and a generous amount of black pepper. Stir to combine, then cover and cook on low for 4 hours.

Add Spinach and Artichokes

Roughly 20 minutes before serving, add the frozen spinach and marinated artichoke hearts. Continue cooking on low until the spinach is thoroughly warmed and can be incorporated into the stew. Adjust the timing based on the form of frozen spinach used (blocks may take longer).

Incorporate Cream Cheese and Herbs

Stir in the cream cheese and fresh dill, allowing the cream cheese to melt fully and blend into the stew.

Shred the Chicken and Serve

Using the back of a spoon or a fork, gently shred the chicken into bite-sized pieces. Taste and adjust seasoning with additional salt and pepper if necessary. Serve the stew in bowls, garnished with thinly sliced scallions and grated Parmesan.