In a large skillet, melt butter over medium-high heat. Add onions, salt, and pepper. Cook, stirring occasionally about 8-10 minutes or until onions soften.
Add brown sugar and continue to cook for 15-20 min or until onions are golden brown.
Pour in beer or wine to deglaze, scraping sides and bottom of the pan. Continue cooking for another 2 minutes.
Transfer cooked onions to a mixing bowl. Add remaining ingredients and stir until thoroughly combined.
Spread mixture into a small 8-inch skillet or a 2-cup baking dish and bake for about 20 minutes, until bubbly and golden brown.
Serve with a sliced up french baguette or crackers!