- Peel onion, cut it in half and then slice thinly (see Notes below). 
- Melt butter and oil in skillet, add onion and season with salt and pepper. 
- Add enough tap water to just cover the onions. 
- Cook over slow/medium heat, stirring occasionally, for about 10-15 minutes, until the liquid evaporates. 
- Start stirring the onion constantly for a few minutes, until brown and caramelized. 
- Allow them to cool down to room temperature. 
- In a bowl mix cream cheese, sour cream, mayonnaise, and cooled onions, saving a tablespoon for garnish. 
- Add cayenne, 1 tablespoon milk or cream, and mix well. Make sure the consistency is the right one so the potato chips don't break when scooping it. Add a teaspoon or more liquid if necessary. 
- Check for seasonings and adjust as necessary. 
- Mix in chives, saving a teaspoon for garnish. 
- Serve at room temperature topped with some caramelized onions and chives. 
- Eat with potato chips. 
- Keep leftovers refrigerated.