Slice and peel the onions into rings and then separate them.
Put a skillet over medium heat and add the butter once it is hot.
Melt the butter and then add the onions. Stir occasionally.
Add the broth a few tbsp at a time so that the onions don't burn. Stir occasionally and add more broth as the broth will get absorbed. This will take about 25-35 minutes.
Once the onions and broth were golden and the liquid absorbed, take off the heat and then add the Worcestershire sauce. Let cool completely.
In a bowl, add the sour cream, mayonnaise, garlic powder, salt, and pepper. Stir in the cooked onions.
Put the dip in the fridge for 1 hour and then serve.