In a large Dutch oven over medium-high heat, melt the butter. Add the onion, season lightly with salt, and cook, stirring occasionally, until softened and translucent, about 5 minutes. Add the celery and cook, stirring, until softened, about 5 minutes, adjusting the heat as necessary to avoid scorching. Stir in the garlic.

Pour in the stock and wine, and bring to a bubble. Add the chicken thighs, lemon juice and red-pepper flakes; season with 1 teaspoon salt and a generous amount of pepper. Mix well to combine all the ingredients and bring to a boil.

Reduce the heat to maintain a low simmer and simmer, uncovered, for 20 minutes.

Add the frozen spinach and the artichoke hearts to the pot. Increase the heat to medium-high and cook, stirring to help the spinach defrost and wilt into the stew. When the spinach is warm and evenly distributed, reduce the heat and simmer until the chicken is tender and the flavors are blended, another 10 to 15 minutes.

Add the cream cheese in dollops, stirring to melt it into the soup. Add the dill. Using two forks, coarsely break or shred the chicken into large chunks. Taste and add more salt and black pepper if necessary.

Divide the stew among bowls, and top with scallions and Parmesan.