Heat the butter and olive oil in a large skillet over medium heat.
Add the sliced onions and toss to coat evenly in the butter-olive oil mixture.
Stir in thyme, honey and pepper.
Cook, stirring occasionally, until golden brown. This should take about 12 - 20 minutes, depending on the pan you are using and the moisture content of the onions.
Remove the pan from the heat and add the whiskey and white balsamic vinegar. (Remove the pan so the alcohol doesn't ignite!)
Return the pan to the stove and turn to high heat, bring to a boil then turn down to simmer.
Simmer until the moisture is reduced and mixture thickens to a jam like consistency, about 20-30 minutes.
Notes
Gr8 Do-Ahead Tip:
This can be made, cooled, then stored in a sealed container in the refrigerator for up to a week.
Gr8 Tips:
This is best when served over steaks with a horseradish cream sauce.
Serve this on top of crostini with some brie or a slice of pear.