Melt butter in a large saucepan over medium heat. Add herbs and pepper, cooking until fragrant (~30 seconds). Whisk in turkey base and flour, cooking 1-2 minutes until golden. Gradually whisk in broth, cooking 3-4 minutes until thickened. Let cool, then store in an airtight container in the fridge up to 5 days.
Reheat gravy over medium-low, whisking until warmed (~5-8 minutes). Prepare drippings by skimming fat from roasted pan, then stir into gravy. Whisk in additional broth if needed, season to taste, and keep warm until serving.
Notes
For extra flavor, stir in drippings during reheating and adjust seasoning as needed.