You can create the cheesy, saucy, caramelized onion-y fries at home.
Prepare fries according to package directions.
In a large skillet, heat oil over medium-low heat. Add onions. Cook about 20 to 25 minutes, or until caramelized stirring occasionally. Increase heat to medium-high and add water, scraping the brown bits off of the bottom of the pan. Remove from heat. Set aside.
In a medium bowl combine next six ingredients (through pepper).
Top fries with cheese slices, caramelized onions, and drizzle with mayonnaise mixture.