The Wordsmith's Forge

I know Larry Niven wrote about two tidally locked worlds in his Known Space stories. However, they're both exceptions to the rule. The first was Mercury in "The Coldest Place." That was when astronomers thought the planet was tidally locked. We now know it's not. The other was Jinx, a moon of a gas giant around Sirius. Niven did his best description of it in "Borderland of Sol," describing it as a giant Easter egg. However, it was tidally locked to the gas giant, not Sirius, so it wouldn't be an "eyeball planet."