Worcestershire paceman Matt Henry broke the Essex second wicket partnership of 222 between Alastair Cook and Tom Westley on the second day of the Specsavers County Championship clash at New Road.
The New Zealander struck for the second time in the innings when he trapped Westley lbw for 125 with the total on 238 in the 66th over.
But it was hard work for the County bowlers on a good pitch on another truncated day after bad light and rain meant 46 overs were lost.
England Test captain Cook showed his class in making 130 not out from 254 balls with one six and 20 fours and has so far added an unbroken 97 with Ravi Bopara (48 not out) as Essex closed on 335-2 from 90 overs.
Essex resumed on 144-1 after only 40 overs had been possible on the opening day with Cook unbeaten on 53 and Westley on 70 not out.
The County opened their attack with Jack Shantry and Henry who had taken the only wicket to fall yesterday.
Westley and Cook reeled off a successive of impressive boundaries although the former had a slice of good fortune when twice edging Henry to the boundary.
A single on the legside off Ed Barnard brought up Westley's hundred off 163 balls with 17 fours and one six out of 188-1 in the 55th over.
Westley then attempted to hook Joe Leach and the ball ended up going for four through long on!
The 200 partnership came up in 56 overs but bad light led to the players leaving the field at 12.20 and an early lunch was taken at 12.35.
Westley was unbeaten on 122 and Cook 83.
Persistent rain set in during the afternoon and play did not restart until 4.45 with 28 overs remaining.
Westley added only three more runs to his tally before Henry ended his fine knock.
Ravi Bopara came to the wicket and helped Essex top the 300 mark in the final over before the second new ball became due although it was not taken.