Make the graham cracker crust. If starting with whole graham crackers, either pulse them in a food processor or smash them into crumbs with a rolling pin. (For the latter, put 3-4 graham crackers into a large freezer ziploc at a time and roll them with the pin until they’re fine crumbs.) Add sugar, melted butter, and salt and mix well with a fork.
Pour crumbs into a 9” pie dish or baking pan and press down with a large tablespoon, your hands, or a drinking glass until flat on the bottom and well pressed together along the sides. Chill in the refrigerator for an hour or you can bake the crust in a 325F oven for about 10 minutes, until fragrant. Let crust cool completely before filling.
Meanwhile, make the topping and the filling.
For the topping: Cut the watermelon into very small pieces. Think chocolate-chip size. Then in a medium bowl, stir together the watermelon, lime juice, sugar, and salt. Once well mixed, pour the watermelon mixture into a fine mesh strainer. Then put the strainer on top of the bowl you were using so the watermelon juices drip into it. Cover the stacked strainer and bowl and let rest in fridge for at least two hours. You want most of that excess watermelon juice to drain out.
For the filling: In a medium bowl, add all ingredients except powdered sugar. Beat well (I used an electric mixer) until smooth. (But it’s OK if there are still tiny clumps of feta; they seemed to sort of dissolve during the chilling step.) Sift sugar into the bowl and mix, starting very slowly so the sugar doesn’t poof up all over the place. Chill cheese mixture in it’s bowl in the refrigerator until the crust is ready.
When ready to assemble, pour filling into the crust, smoothing the top with the back of a clean tablespoon. Chill for 2 hours before topping.
Add watermelon topping and sprinkle with some fresh chopped basil.
Trick yourself into thinking this is healthy because, hey, it was inspired by a salad!
Sifting the sugar into the bowl for the filling is to get rid of some of the lumps in the finished product. It is still somewhat lumpy due to the ricotta cheese, so if it doesn’t bother you, then by all means skip the sifting.