Preheat oven to 350 degrees F. Lightly butter a 2 quart or 9x13 baking sheet.
Melt butter into a medium saucepan over medium-high heat.
Whisk in flour and cook for 1 minute to cook off the raw flour taste.
Slowly whisk in the wine and garlic, whisking until thickened.
Add in the chicken broth ¼ cup at a time, whisking to incorporate. Add in the salt, pepper, and thyme and bring the mixture to a simmer. Simmer, whisking often, until the sauce has thickened enough to coat the back of a spoon.
Reduce heat to medium-low and then stir in 2 cups of cheese until melted. Turn off heat and stir in the cooked rice and chicken.
Transfer to a 9×13 inch baking dish. Top with remaining cheddar cheese and bake for 25-30 minutes or until cheese is melted through.
Thyme Leaves: If you don't have fresh thyme--do not worry!! It adds an extra layer of flavor that I enjoy but is completely not necessary. You can substitute ½ teaspoon of dried thyme leaves works as well. Do not use ground thyme. The flavor is overwhelming. Wine: White wine adds a rich depth of flavor to this chicken and rice casserole, but is not necessary, just replace it with an additional ¼ cup of chicken stock. If using wine, use a dry chardonnay or pinot grigio.Garlic: This recipe has a lot of added garlic, feel free to cut the amount in half, if you are sensitive to high amounts of garlic. Storage: Store leftover chicken and rice casserole in a covered container for up to 3 days. Freeze for up to 3 months. Make-Ahead Instructions: To prepare this casserole in advance, prepare up to baking. Cover tightly with 2 layers of foil. Refrigerate for up to 3 days or freeze up to 3 months.
To bake from the fridge, remove casserole from the fridge and remove 1 layer of foil. Preheat oven to 350 degrees, letting the casserole sit on the counter while the oven preheats. Bake for 30-40 minutes or until warmed through.
To bake from the freezer, remove casserole from freeze and remove 1 layer of foil. Bake at 350 degrees for 60 minutes covered and then uncovered for 15 additional minutes.