Shane Horgan again proved a thorn in the Scarlets' side
Leinster kept pace with chief rivals London Irish at the top of Heineken Cup Pool Six with a seven-try dismissal of the Scarlets at the RDS Showgrounds.
Rob Kearney, Gordon D'Arcy and Brian O'Driscoll grabbed two tries each.
Shane Horgan also crossed for an 80m interception effort, while the Scarlets' only response came from Rhys Priestland in the final quarter.
The result keeps the defending champions on course for a pool decider with the Exiles in Reading next month.
Both sides are locked together on 15 points ahead of the final two rounds of group matches.
As in last weekend's 32-7 victory at Parc y Scarlets, three first-half tries set the tone for Michael Cheika's men against a Scarlets side that struggled to maintain any sort of attacking momentum.
The key moment came just before half-time when, just as the Scarlets looked set to cross the Leinster try-line, Deacon Manu's pass was intercepted by Horgan, who outstripped Stephen Jones and Priestland to finish from 80 metres out.
The visitors made a confident start but Jones missed two reasonable penalties and Leinster - who dominated at the breakdown and the scrum, took advantage.
Full-back Kearney dropped three high balls in the opening quarter but took a pass from Horgan to slide home at the left corner after eight minutes.
Shaun Berne, struggling with his place-kicks into an icy wind, missed the first of several conversion attempts, the second when the impressive Horgan gathered Berne's crossfield kick and fed Kearney to score his second try.
Sean Lamont, David Lyons and player-coach Simon Easterby, who competed tigerishly in his 200th appearance for the club, helped the Welsh region rally before half-time.
But just when they appeared to be on the verge of scoring themselves, Horgan snaffled Manu's pass and sprinted home to put the hosts 15-0 up at the break.
The bonus point was secured within six minutes of the resumption as D'Arcy danced through from close range after a break from Isa Nacewa and good work from man-of-the-match Jamie Heaslip on his 100th Leinster appearance.
Berne broke his kicking duck with the successful conversion and O'Driscoll was soon muscling his way over for the fifth try.
A superb catch by Kearney, a barnstorming run from replacement hooker Bernard Jackman and a sweet feed from Berne gave D'Arcy' his second try, which Berne converted.
Starved of territory, the Scarlets lifted the siege just past the hour when Kearney misjudged the bounce of the ball and Priestland hared through for a consolation try.
But, showing no mercy, Leinster had the final say when replacement Fergus McFadden fed O'Driscoll for a simple score in the left corner.
Leinster: Rob Kearney; Shane Horgan, Brian O'Driscoll, Gordon D'Arcy, Isa Nacewa; Shaun Berne, Eoin Reddan; Cian Healy, John Fogarty, CJ van der Linde; Leo Cullen (capt), Nathan Hines; Kevin McLaughlin, Sean O'Brien, Jamie Heaslip. Replacements: Wright for Van der Linde (28), Jackman for Fogarty (51), S Keogh for O'Brien (51), O'Kelly for Hines (52), Ross for Healy (57), McFadden for D'Arcy (60), Dempsey for Nacewa (60), O'Donohoe for Reddan (73).
Scarlets: Rhys Priestland; Darren Daniel, Sean Lamont, Jonathan Davies, Andy Fenby; Stephen Jones, Martin Roberts; Iestyn Thomas, Ken Owens, Deacon Manu, Lou Reed, Dominic Day, Simon Easterby, Johnathan Edwards, David Lyons (capt). Replacements: Maule for Fenby (16), Knoyle for Roberts (55), John for I Thomas (55), McCusker for Edwards (55), Evans for Knoyle (64), Corsi for Manu (70), Phillips for Owen (71), Cooper for Day (71).
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