After searing and removing the protein, add the aromatic to the pan over medium heat and cook until softened, about 1 minute.
Deglaze with the first liquid, scraping the pan to lift the fond.
Add the second liquid and reduce over medium-high heat until visibly thickened, about 5–8 minutes.
Remove from heat and swirl in the cold butter, a piece at a time, until smooth and glossy.
Season to taste, stir in herbs if using, and serve immediately over the rested protein.