Transfer the liquid to a fat separator and let sit for 5 minutes to allow fat to separate. Return 2/3 to 3/4 cup of the fat to the roasting pan and place over medium-high heat. Discard any remaining fat. Add the flour and whisk to combine. Cook, whisking continuously, until the mixture starts to thicken and become smooth, 2 to 3 minutes. Once this happens, gradually add the liquid back to the pan and whisk until smooth and you have reached your desired consistency, 5 to 6 minutes. Remember, your gravy should be slightly thin in the pan as it will thicken once you serve it. Add the herbs and whisk to combine. Season with salt and pepper.