The attacking midfielder registered after 11 and 23 minutes before completing his treble from the penalty spot with the seventh and final goal in the 7-2 win 15 minutes from time.
It was the team's first victory in the new Barclays U21 PL at the fourth attempt and no less impressive than the first team's performance at Reading on Sunday.
Yago Falque took just 25 seconds to underline the team's intent, his curler from 25 yards needed a decent tip over from Dale Eve in the Stoke goal.
Stoke then took the lead against the run of play in the sixth minute as Jordan Keane found himself clear from a corner and rammed the ball home.
The response was immediate as Falque rattled the crossbar and it was soon 1-1 as Falque chipped a cross to the far post where Mason powered home his header.
It was 3-1 in the blink of an eye. Cristian Ceballos gave us the lead after 14 minutes, initially winning a 50-50 before picking himself up, collecting Falque's pass and sliding home past Eve.
Seconds later, Jonathan Obika charged down Eve's attempted clearance and the ball looped into the empty net.
Nathan Byrne and Adam Smith looked to get forward from full-back throughout and Byrne curled home a beauty off the post from 25 yards to make it 4-1 after 23 minutes.
Obika and Tom Carroll went close before Stoke pulled a goal back on 39 minutes. Michael Clarkson got to the left byline and crossed low for Lucas Dawson to finish at the second attempt.
Mason had the final word of the first half with arguably the goal of the game.
Dean Parrett floated a ball up to Obika, who won a towering header into the path of supporting Mason, who buried a first-time volley from 16 yards.
After a quiet start, the second half came to life just after the hour mark with another fine goal.
Carroll darted to the right byline and cut the ball back to the near post where Parrett cushioned home a lovely volley from eight yards for 6-2.
Ceballos then struck the post from 20 yards and a couple of penalty appeals were turned away before Keane upended Smith in the box and Mason planted his hat-trick goal home from 12 yards.
Spurs U21s (4-2-3-1): Archer; Smith, Hall, Veljkovic (Stewart, 68), Byrne; Carroll (Dombaxe, 68), Parrett; Ceballos, Mason, Falque; Obika (Munns, 68). Unused subs: Vigouroux, Ekong.
Stoke (4-5-1): Eve; Rigg, Parry, Keane, O'Rielly; Thomas, Clarkson, Dawson (Scott, 72), Richardson, Nardiello (Hall, 72); Obiake. Unused subs: Gledhill, Rossi, Glasgow.