In a medium skillet melt the butter over medium heat. Add the onions and stir.

Reduce heat to medium low and cook, stirring occasionally, until the onions begin to brown.

Sprinkle the onions with salt and pepper and cook for an additional 10
minutes, stirring occasionally.  Stir in the garlic and cook for 5 more minutes or until the onions are caramelized.  Remove from heat.

In a medium bowl combine the sour cream, cream cheese, and lemon juice.  Mix until smooth.

Add in the caramelized onions, reserving a few for the top of the
dip, and the chives. Mix well until combined. 

Place the reserved onions on top.

Serve with vegetables, chips, or crackers.