A "good" one? Well, as I once noted, here's what it's not: sickly sweet, the filling thick and doughy, or overspiced or runny wet or so dark and dense with molasses that its potato-ness is lost.
What it is instead - by my lights at least - is "moist and vegetal, fragrant with nutmeg (or sometimes coconut), the sweet tamed by lemon, the egg-leavened filling given dimension by a little orange zest, crushed pecan, or fresh ginger."
So, yes, I was disappointed I couldn't get my nose down into a good slice at the academy's contest on Logan Square.
But last Sunday - jogged by a column Jessica Harris, the African American cookbook author, did on the conjunction of Lincoln's declaration of Thanksgiving as a national holiday in 1863, a year after issuing the Emancipation Proclamation - I was moved to head over to the Carver exhibition for a belated look.
Harris had taken as her text the journey of African slaves to America, and their adoption of the sustaining sweet potato in place of the true African yam (a large, hard, hairy tuber), the culinary star of their homeland.
How achingly remarkable, she wrote in that piece in the New York Times, that 150 years after that first Thanksgiving proclamation, the first family is "a direct reflection" of the Emancipation Proclamation that had preceded it.
She hoped that in that spirit - and as a symbol of that American journey - the White House would have a good sweet potato pie on the family's Thanksgiving table.
Well, the White House did, in fact. And it was something of a tribute as well to another extraordinary American journey - that of George Washington Carver, born a slave, who became one of the country's most admired applied scientists.
