The striker - lining up centrally in the forward midfield three in a 4-2-3-1 system - netted once in the first half and completed his treble with two confident finishes as we kicked into overdrive in the second half at Roots Hall.
Earlier, Souleymane Coulibaly opened the scoring with arguably the goal of the night - certainly the best finish - with Andros Townsend and Jonathan Obika also on target.
Our quick interplay in the central areas with Townsend and Yago Falque always a threat down both flanks and Adam Smith often an extra attacker had the home team on the back foot from the start.
It took 16 minutes to open the scoring when Townsend got the the left byline and crossed for Coulibaly at the near post.
There was little for the young Ivory Coast striker to aim at from such a tight angle, but he hit the spot, striking the ball high into the top corner.
Kane went close twice and Townsend saw his free-kick touched onto the crossbar by Daniel Bentley in the Southend goal before we doubled the lead on 37 minutes.
It was a quick break and the team worked a man advantage well as Falque played in Smith on the overlap, Tom Carroll saw his shot blocked but Kane was there to sweep home the rebound from close range.
At the other end, Southend, led in attack by veteran Neil Harris, wasted their best chance when Harris flicked on Anthony Straker's cross only for Ryan Leonard to head over from 12 yards.
The second half was more one-sided as the football started to really flow.
One of the best moves of the game five minutes into the half involved five players, with Carroll and Coulibaly opening it up for Townsend down the left. The winger fizzed in a low cross that somehow evaded Kane and Coulibaly sliding in and when Falque reached it, his goalbound effort struck Kane in front of goal.
Carroll curled inches wide and the third goal wasn't far away as Carroll and Kane combined, Carroll's slide-rule pass right of centre given the finish it deserved by Kane, who lifted the ball casually over the advancing Bentley.
It was 4-0 a minute later as Townsend tried his luck from distance and his shot clipped off Sean Clohessy, leaving Bentley wrong-footed.
Kane's hat-trick goal arrived on 74 minutes and was similar to his second and our third, this time Townsend found the inch-perfect pass just right of centre and Kane placed his sidefoot firmly inside the near post.
The sixth and final goal inevitably involved the outstanding Townsend and Kane as Townsend crossed to the far post, Kane nodded back across goal and substitute Jon Obika powered home his header from close range.
Southend United (4-1-3-2): Bentley; Clohessy, Phillips, Prosser, Straker; Leonard (Hurst, 64); Spicer, Ferdinand, Hall (Martin, 64); Harris (Benyon, 52), Eastwood.
Spurs XI (4-2-3-1): Ryan (Priestley, 82); Smith, Ekong (Stewart, 70), Hall, Rose; Carroll (Pritchard, 70), Mason; Falque (Gomelt, 74), Kane, Townsend; Coulibaly (Obika, 61).
Goals: Spurs XI - Coulibaly (16), Kane (37, 66, 74), Townsend (67), Obika (82).
Referee: Mr F Graham.