1. Melt the butter (or heat the oil) in a large skillet over medium heat. Once hot, add the onion and sauté, stirring occasionally, until it starts to soften and become translucent, about 8 minutes. Add the garlic, and cook another 1-2 minutes, stirring frequently.
2. Add the broth and stir to scrape up any bits that have collected in the skillet, then transfer to the slow cooker.
3. Add the peppers, spices, and chicken thighs and stir well. Cook on low for 4-6 hours, or until the chicken is cooked through and the peppers are tender.
4. Once the paprikash has finished cooking, transfer the chicken thighs to a plate, and cut or shred into bite-sized pieces if desired. Remove about ¼ cup of liquid from the slow cooker and combine it in a small bowl with the arrowroot, using the back of a spoon to make sure there are no lumps. Add the arrowroot mixture to the sour cream and mix well. Add the mixture to the slow cooker and stir well. Allow the paprikash to cook a few minutes to thicken, stirring occasionally.
5. Once thickened, spoon the vegetables and sauce over your chosen base and then top each with a serving of chicken. Alternatively, add bite-sized pieces of chicken and any juices that have accumulated on the plate back to the slow cooker and then serve over your desired base.