Town dominated the early exchanges, with Thomas being denied by the upright within the first five minutes.
It wasn't long before Denham cracked under the pressure being applied and found themselves behind as Ipswich defender Cooper rose highest to meet Natalie Richardson's corner, powerfully heading Town in front through the fingertips of goalkeeper Lizzie Rose.
Frustrations from the Denham bench began to show and in a bizarre turn of events, assistant-manager Harrison Williams was dismissed for dissent after a strong challenge from Town forward Toni-Anne Wayne was waved away by the referee.
Ipswich continued to pile on the pressure before the break and could have been two in front but Richardson's dangerous free-kick couldn't be turned in by neither Cossey or Wayne.
After the restart Cossey atoned for her earlier miss and bagged herself yet another trademark goal, cutting in from the left and smashing the ball into the top corner to double Town's advantage.
Ipswich made it three just five minutes later with Thomas next to add to her tally. Wayne held the ball up, broke into the area and laid the ball across goal for the arriving Thomas, who followed up at the second time of asking after her initial strike was blocked.
The relentless barrage of Ipswich attacks kept coming, with Cooper unlucky not to have her second of the afternoon as her glancing header was clawed out of the air by Rose.
The visitors simply couldn't withstand the pressure, with Thomas - a constant threat for Town- going close a number of times before finally netting her second of an impressive afternoon as she followed up on the rebound after substitute Sophie Welton's initial fizzing effort struck the bar.
The ruthless Tractor Girls asserted their dominance right until the final whistle with back-to-back wins and clean sheets now seeing them rise to 3rd in the Women's National League Division One South East table.
Town XI: Fagg (GK), Moore, Petley, Cooper, Ball, Craddock (c), Wakefield (Campbell), Thomas, Cossey, Richardson, Wayne (Welton).