Add butter to a skillet and melt completely; turning the skillet around to coat.
Drain juice from diced tomatoes and reserve juice.
Add garlic to the skillet and stir often while it cooks.
Once garlic is golden brown, add the reserved tomato juice. Bring butter-garlic-tomato juice to a low simmer.
Rub chicken breasts with some olive oil, salt, pepper, and rosemary.
Add chicken breasts to the skillet and brown on each side; about 3-5 minutes.
Preheat oven to 350 degrees Fahrenheit.
Once chicken has browned, add the diced tomatoes to the skillet and place in the oven for 10 minutes to completely cook through. (If your skillet is not oven-safe, transfer contents of skillet to an oven safe casserole dish.)
Once chicken is cooked through (to an internal temperature of 165 degrees Fahrenheit), remove from oven.
Season with salt, pepper, and/or lemon zest/juice, to taste, before serving.
Serve atop quinoa to make a complete, delicious meal.