Immediately after removing roasted meat from its pan, drain off drippings, reserving 2 tablespoons in the pan.

Sprinkle flour over drippings; cook and stir over medium heat until brown. Gradually stir in milk, whisking with a fork to scrape up all of the meaty bits from the pan, then gradually whisk in water.

Increase heat to medium-high; cook, stirring constantly, until gravy thickens, about 10 minutes. Season with salt and pepper.