Second-half goals from the pair added to Juan Mata's early goal to put Benitez's men through to the quarter-finals of the Europa League, despite Vlad Chiriches's goal
Juan Mata's strike cancelled out the away side's 1-0 first-leg advantage before Vlad Chiriches levelled proceedings from a corner just prior to the half-time interval.
A storming second-half header from John Terry was followed by a smart finish from Torres and, even though the Spaniard missed a late penalty in an attempt to extend their lead, it proved unimportant as Steaua could not force a late leveller.
Rafa Benitez made four changes from the side that overturned a two-goal deficit to earn a 2-2 draw against Manchester United, with Terry, Torres, John Obi Mikel and Eden Hazard coming in to replace Gary Cahill, Frank Lampard, Victor Moses and the cup-tied Demba Ba.
Steaua , meanwhile, named the exact same team that managed a surprise 1-0 win over the Blues in the first leg.
After a tepid opening, the first chance fell the away side's way with 10 minutes gone as a mix-up between Mikel and Terry allowed Raul Rusescu in on goal; the first-leg goalscorer was unable to capitalise on his one-on-one, though, as Petr Cech made an excellent save, tipping the Romanian's effort wide.
Chelsea opened the scoring with just over half an hour gone as, Mata picking up the ball on the halfway line and advancing before playing a lovely one-two with the driving Ramires. The diminutive Spaniard let the return pass run onto his right before striking with his weaker foot, the ball squirming past Tatarusanu.
The Blues began to run riot as Torres went close at the near post, striking wide after receiving the ball from Mata, before Hazard, clearly enjoying himself, played a lovely one-two with Mata before striking the ball goalwards, forcing another adept save.
Despite the hosts' increasing dominance, Steaua shocked Stamford Bridge by getting a goal back just prior to the half-time whistle. Torres, back in his own area for a corner, failed to clear the set-piece at the near post and Cech could only parry Cristian Tanase's ensuing close-range shot. The rebound fell Chiriches's way and he made no mistake in his finish, firing into the roof of the net to make it 1-1 at the interval.
Chelsea soon struck back after the break as Terry put them level on aggregrate, albeit still behind due to Steaua's away goal. After Hazard was felled cynically by Rapa on the left wing, Mata whipped in a dangerous ball and the centre-back converted the cross with aplomb, heading powerfully home to make it 2-1.
The home side continued to test the away side and eventually capitalised, with Torres finally breaking his duck to extend Chelsea's lead. After the typically lively Mata placed a ball into the path of Hazard, the continually impressive Belgian dummied the ball, letting it run into the striker's feet. Torres took the ball onto his left with one step before striking the ball into the far corner smartly.
Torres had a golden chance to truly end the game as, after Hazard was felled in the penalty area, he took on the responsibility of the spot kick. The striker got the penalty wrong, though, firing against the crossbar - thankfully for the Spaniard, it did not have a bearing on Chelsea's progress as Steaua proved unable to get a late goal.