Place vegetables on bottom of crock-pot. Place meat on top. Season with salt and pepper. Pour about 3 tablespoons of water into the pot. Cook on Low for 10 to 12 hours.
Remove meat and vegetables to large serving dish or bowl, cover to keep warm.
Make gravy by making a smooth paste of 3 tablespoons of flour and 1/4 cup water in a 2-cup measuring cup. Slowly ladle hot juices into the flour mixture, stirring constantly. Once the measuring cup is full, pour gravy mixture back into crock-pot and blend with remaining juices. Either pour gravy over meat and vegetables, or serve gravy separately.