1. Melt the Butter in a Medium Saucepan: Place a medium-sized saucepan over medium heat. Add the unsalted butter and let it melt completely. Swirl the pan gently to coat the bottom evenly. You want the butter to be fully liquid and slightly shimmering, but not browning.

2. Whisk in the Flour to Create a Roux: Once the butter is melted, sprinkle the all-purpose flour over the melted butter. Immediately begin whisking continuously. Continue whisking for 1-2 minutes, until the mixture forms a smooth, pale golden paste, known as a roux. This step is crucial for thickening the gravy and cooking out the raw flour taste.

3. Gradually Add the Broth While Whisking: Slowly pour in about 1 cup of the chicken or turkey broth into the roux, whisking constantly to incorporate it smoothly. The mixture will be very thick at first. Continue gradually adding the remaining broth, about 1/2 cup at a time, whisking vigorously after each addition until the gravy is smooth and lump-free.

4. Bring to a Simmer and Thicken: Increase the heat slightly to medium-high and bring the gravy to a gentle simmer, continuing to whisk occasionally. As it heats, the gravy will begin to thicken. Let it simmer for 5-7 minutes, or until it reaches your desired consistency. It should be thick enough to coat the back of a spoon.

5. Stir in Seasonings: Reduce the heat to low. Stir in the dried sage, black pepper, and salt. Taste the gravy and adjust the seasoning as needed. You might want to add a little more salt or pepper, depending on your preference and the saltiness of your broth.

6. Serve Warm: Remove the gravy from the heat and serve immediately. If you’re not serving it right away, keep it warm over very low heat, stirring occasionally, or transfer it to a warmed gravy boat.