Heat a heavy-bottomed skillet over medium heat.

Add the butter and allow it to melt.

Add the sliced onions, salt, and sugar, and stir together.

Allow the onions to cook over medium/medium-low heat and stir every few minutes to keep the onions from sticking to the bottom of the pan.

When the onions start to stick to the pan, add a splash of the wine and stir to scrape all the brown bits off the bottom. Continue the process of cooking, splash of wine and stirring until everything is reduced and the onions are a dark golden brown.

Place the onions on a cutting board and roughly chop the onions into smaller pieces.

In a medium bowl, combine the sour cream and cream cheese and whisk to combine and smooth out.

Add the onions and the minced parsley and stir to fully combine.

Add minced garlic and Worcestershire sauce. Stir to combine.

Serve warm immediately or cover and refrigerate until ready to serve.