This dish is rich, warm, and just comforting. I can have this on its own, with some crusty bread, or over a bowl of rice. It's just that good.
Start off by seasoning those chicken pieces with salt, black pepper, and some dried thyme. Some cinnamon would be great as well. Just go with whatever aromatic you already have in your pantry. No need to shop for thyme specifically. Thyme in my opinion just has that slightly lemony after-note that goes well with the subtle flavor of chicken.
Melt a full stick of butter in a skillet. This'll serve all to brown the chicken pieces, impart a rich nutty flavor, and form a base for our roux that will thicken this chowder. Yes, I said chowder. Who said chowders have to come with food in tiny chunks? I like my chicken bone-in for the depth of flavor those bones will render to the creamy broth.
Add the chicken in skin-side down first. Doing so will give the skins a perfectly golden color. Butter will brown quicker than most oils. Putting the chicken flesh side down first will mean that the skin will be cooking in butter that has already browned a bit as you flip them over.
Set the seared chicken pieces aside and sautee all your aromatics and veggies. The corn, celery, and onions will turn out sweeter if you allow them to caramelize a bit in oil. Also, try to cut them in uniform sizes – much like that of a corn kernel. This chowder will cook relatively quick so cutting them tiny would get the most flavor out of them. Before the vegetables begin to scorch, deglaze the pan with some white wine. Scrape any pan drippings lose as you allow the wine to reduce completely.
Next, create a roux. Dust the flour into that mixture of oil and melted butter. This flour will act as a thickener to give some body to our sauce. So why not just add a slurry of flour and water in the end? Well, let me explain on some points. Roasting flour in a bit of fat(yes, a roux doesn't have to begin with butter exclusively) gives you the flexibility to change the tone of the resulting cream sauce.
Roasting it lightly is perfect for cream sauces, while allowing the flour to turn dark brown will give gravies a deeper brown color. Next, flour, unlike starch must be allowed to simmer in a sauce for a minimum of 15 minutes in order to get rid of its raw(floury) taste. Since we're cooking a chicken dish, which relatively needs a shorter amount of time, the flour may not have a chance to get ‘fully cooked'.
Next, add in the milk and chicken broth while whisking continuously. Here's a tip for making lump-free starch-thickened sauces: there must be a temperature contrast between your thickener and your base liquid. In this case, use cold milk to go into the hot roux. Using warm milk would cause the flour to produce lumps.
Add this sauce to the slow cooker, put in the chicken, and some potatoes, or any more vegetables you'd like, and cook everything on low for about 4 hours.