Spaven, 23, previously made 27 appearances for the Dons in 2011, before moving on to Dewsbury, but he left the Rams earlier this year and turned to amateur rugby league.
He said: “Looking back to April it was a pretty tough decision to leave Dewsbury as I had just been made captain but I had to do what was right for my family.
“Travelling up and down the M62 three times a week got too much in the end as I had to be as close to home as possible.
“However, it presented me with the opportunity to play alongside my brother at West Hull which was good and I started enjoying my rugby again.
“Coming back to Doncaster was quite an easy decision to make and Cookie was certainly an influence in my return.
“As I play at scrum half or hooker I feel I can learn a lot from him as he’s a smart bloke and I also feel the club is making great progress and is heading in the right direction.”
Cooke said: “Scott’s another excellent signing for the club and brings a wealth of experience with him from his time with Hull KR and Dewsbury.
“After things didn’t work out for Scott at Dewsbury, we kept in touch and tried to bring him back when Kyle Kesik injured his knee earlier in the season but he stayed with West Hull for family reasons.
“He keeps himself in great physical condition, has a very good attitude towards the game and has a desire to succeed.
“I believe he’s another player who has the right pedigree to add to our culture and professionalism as we continue to move forward.”