Steven Naismith, Jamie Walker, Elliott Frear and Josh Ginnelly also scored for the leaders.
Liam Boyce took his tally for the season to five with a brace in Hearts' 6-1 win over Queen of the South.
Steven Naismith opened the scoring for the leaders with a superb swerving strike from 25 yards that went in off a post after 20 minutes.
It should have been 2-0 five minutes later when Naismith's chipped pass to Boyce forced a fine save from Jack Leighfield and Olly Lee somehow blazed over the loose ball from close in.
Queen of the South spurned a good chance to equalise shortly afterwards when Connor Shields lobbed Craig Gordon but the ball cleared the crossbar.
Hearts made them pay with a second goal in first-half stoppage time as Boyce powered in a header from Lee's pinpoint cross.
And Boyce added a third immediately after the restart, turning in a low cross from Aidy White.
The visitors pulled a goal back after 72 minutes when Ayo Obileye got on the end of a free-kick at the back post, but Hearts restored their three-goal cushion when Jamie Walker slammed the ball home four minutes later.
Elliott Frear tapped in a fifth eight minutes from time and Josh Ginnelly sealed a thumping victory with a 25-yard piledriver in the first minute of time added on.