After cooking your meat, pour off all but two tablespoons of leftover cooking oil or rendered fat from the pan. Homesteading Hack: If you are making your sauce in a new pan, melt your two tablespoons of fat in the pan.
Sauté the onion until golden brown, about 2 1⁄2 to 3 minutes.
With the pan on medium-high heat, pour in the juice (or wine or additional broth).
As the liquid reaches a simmer, scrape any crispy browned bits from the bottom of the pan with the spatula.
Let simmer for about 3 minutes or until reduced by half.
Pour the remaining stock into it and stir until combined.
Let the sauce come to a rapid simmer.
Reduce the liquid by half to about 1 cup. This should take 3 to 5 minutes.
Once the liquid is reduced, lower the heat to medium-low and stir in the butter or cream. Whisk gently until the butter has completely melted.
Continue to simmer until slightly thickened.
Pour your sauce into a serving cup and add salt and pepper to taste.
This sauce will be best when used right away.