Things the OU head coach is bad at ... brisket -- clearly.

The 37-year-old Sooners head man showed off his Easter dinner on social media Sunday ... and the meat he cooked was so dry, some questioned whether it was actually pumpernickel!!

Check out the photo Riley shared ... the meat was cooked to a crisp -- and the poor dude was ROASTED over it!!!

The comments were relentless ...

"Dear Lord, please see what real TX brisket looks like and never cook a brisket again.  Ever."

"If you drop your phone in water you could put it in a bag with this brisket to dry it out."

"This mf loves football so much he eats it for dinner."

"Did you pull that out of Jesus’s tomb?"

"I don’t know why everyone is roasting this. That pumpernickel looks delicious."

For his part, Riley seemed to defend the cooked cow in the wake of the backlash ... writing to one critic, "Haha ask @BwylieSTRONG if it was legit....."

That guy, OU's Director of Sports Performance Bennie Wylie, had Riley's back ... adding, "Unbelievable... Brisket tacos on point!"