In a medium saucepan, melt the butter and whisk in the flour.
Cook over medium-high heat until the flour is incorporated and white bubbles begin to form on the top of the mixture (also know as “roux”).
Cook the roux for 2-3 minutes after the bubbles have formed, whisking constantly. I aim for a blonde-colored roux, which is a shade or two lighter than peanut butter. (Helpful hint: if you’re on the fence about how dark to let the mixture turn, err on the side of lighter than darker. Color equals flavor, however, a dark roux actually has less thickening power, plus any amount of burned roux will make for undesirable gravy.)
Gradually whisk in the broth, followed by the thyme and sage, whisking constantly until the gravy is thickened and comes to a boil.
Remove from the heat and season with salt and pepper. (Amount of seasoning will depend on broth or stock used, personal preference, and how much salt is in the pan drippings to be added later－and you can always add more later.)
At this point, you may use this as a barebones shortcut gravy right away, or cool, cover and refrigerate the gravy base for as long as 4 days. Reheat it in a pot that will accommodate the pan drippings, if using. In that case, when the turkey is done, skim off the fat and pour the drippings into the gravy base－aim for about 2 cups. Adjust seasoning to taste and enjoy.