2
Thinly slice onions and set aside.
3
Melt butter and olive oil in a pan over medium heat.
4
Add onions and a small pinch of salt. Mix to coat.
5
Stir onions every 5 minutes for 30 minutes.
6
Add brown sugar and Worcestershire. Stir every 2 minutes for 15 minutes.
7
Turn heat to low. Add cream cheese, sour cream, mayonnaise, salt, pepper, thyme, garlic powder. Stir.
8
Add 1/2 cup of Gruyère cheese. Stir.
9
Top with more cheese and bake for 7-10 minutes.