Butter or grease a 18 x 13 x 1 baking sheet. Clear a shelf in the fridge and line it with a towel.
In a large stockpot or Dutch oven, heat the water or stock and the milk over a medium high flame until it comes to a simmer. Be careful, the milk tends to foam up and spill over, so make sure you pay attention as the liquid begins to start steaming. As soon as the milk mixture is beginning to bubble, turn the flame down to medium-low and pour in the polenta in an even stream. Whisk constantly as the polenta simmers in the milk until thick as porridge, about 10 minutes.
Add the salt and butter and continue to cook until the polenta is thick enough to stick to the whisk when you lift it up, about 10 minutes more.
Pour the polenta into the prepared pan and smooth it into an even layer with a spatula. Chill the polenta in the fridge, uncovered, until cool and very firm, at least 2 hours or overnight. Note (if overnight, cover the pan with plastic wrap once it’s cooled.)
Preheat the oven to 400 degrees. Line 2 baking sheets with parchment paper.
Using a 1 1/2-inch round cutter, cut the polenta into bite-sized circles and transfer them to the parchment-lined baking sheets, leaving a little space between each one. You can toss the scraps or figure out some other creative use for them.
Bake the polenta in the oven until golden brown on the top and crispy, about 30 to 40 minutes.
Meanwhile, combine the honey and truffle oil in a small bowl. If you want a more pronounced truffle taste, add a few more drops of oil.
Arrange the crispy polenta on a serving platter and drizzle each bite with a little truffle honey and top with a teaspoon or so of ricotta. Serve immediately.