reduce by about half, until it's thick enough (No thickener is used for this sauce, so this is the point where you have the most control over the final thickness.)
adjust to taste — salt, pepper (Note: There may already be a lot of salt in it, so taste first. Significant amounts of salt may have come in via — seasoning the meat, and the stock.)
Articles that discuss it like a "general method for making all pan sauces": [1][2][3][▶4][5][6]