Many gratins trade almost entirely on the richness of heavy cream and cheese, but there is room to modernize—and lighten up—the concept to create a satisfying meatless main course. My plan was to keep the usual crunchy topping but pack the filling with substantial, boldly flavored ingredients. And just because the dish would be vegetarian didn’t mean it would have to lack depth.
I took inspiration from the classic Tuscan dish of beans and greens, a union of white beans and escarole or Swiss chard seasoned with onion, garlic, and red pepper flakes. To turn the dish into a hearty main, it seemed fitting to add another Tuscan staple—farro—to the mix. The tender chew and robust nuttiness of the hulled whole-wheat kernels would round out the gratin.