Despite being ineligible for international duty while playing for Toulon, Ashton was open in the days leading up to the match about his desire to play for his country again.
The winger, who won his last England cap came in 2014, broke the Top 14 try-scoring record in his first season in France and he continued that prolific form by crossing three times on home soil.
Ashton got his first with a trademark dive in the third minute when Toulon team-mate Josua Tuisova handed him the ball on the line, and he quickly made it two by getting on the end of his own chip over Elliot Daly.
He completed his hat-trick as early as the 25th minute, Finn Russell gathering Victor Vito's stunning offload to set up the former Saracens player as the Barbarians ran riot.
Vito touched down twice, while Russell, Tuisova, Semi Radradra, Sitaleki Timani and Greig Laidlaw also crossed for the brilliant Baa-Baas.
Daly, Piers Francis (2), Zach Mercer, Joe Launchbury and Jonny May managed tries for England - who have now lost four games on the spin - in a high-scoring contest.
Next up for Jones's squad is a three-Test tour of South Africa, starting with the series opener in Johannesburg on 9 June.