The superstar ace reportedly just signed a new 9-year, $324 MILLION contract with the New York Yankees ... making him the highest-paid pitcher EVER!!!

Cole was electric for the Houston Astros the past two years ... piling up 602 strikeouts in 412.2 innings, and he finished second in the AL Cy Young voting just a couple weeks ago.

He was the hottest free agent on the market this offseason ... with the Yanks, L.A. Angels and L.A. Dodgers reportedly falling all over themselves to ink the 29-year-old.

But, bidding ended Tuesday night ... 'cause Cole signed the biggest pitcher contract of all-time to move from Texas to New York.

In case you're wondering just how massive of a deal it is ... if Cole makes 33 starts for the Yankees this year like he did for the 'Stros last year -- he'll make more than $1 MIL PER OUTING!!!

As for Cole's agent, Scott Boras ... the dude is SWIMMING in cash this offseason -- he also repped Stephen Strasburg, who signed a $245 MILLION deal this week with the Nationals.

The one downside for Cole to all of this? The Yankees don't allow facial hair, so his beard will have to go in 2019.