Why do vegetable sandwiches always taste better in theory than in practice? What I want is a vibrant and satisfying sandwich, complete with contrasting textures and varying flavors; what I usually get is a soggy mess of haphazardly cooked vegetables that are limp and under-seasoned. Perhaps if I cut back on the number of options and focused on cooking them properly I could correct this problem and make my theoretical ideal come to life? That was the plan, anyway.
I decided to focus on only two vegetables, eggplant and broccoli rabe, but quickly realized I'd have to cook each differently. I sliced the eggplant into 1/4-inch thick sheets, brushed them with oil, and seasoned them all with salt and pepper. Instead of using them right away, I set the slices aside for 30 minutes, which helped to remove excess water and any excess bitterness (the broccoli rabe would certainly have enough of that). Then I cooked them on a grill pan until tender and smoky.
I considered grilling the broccoli rabe, too, but worried that the leaves would finish cooking way before the stalks. Plus, I wanted to lessen the bitter bite. What I settled on was a quick sauté with garlic and red pepper flakes, and then a braise to finish the stalks off. Chicken stock added some richness, though you could use vegetable stock to accomplish the same goal.
The eggplant pieces are tender and meaty, with a distinct profile of smoke, while the broccoli rabe is crunchy, only slightly bitter, with a hint of heat. Some fresh mozzerella slices add creaminess, and a final drizzle of olive oil ties everything together with the ciabatta bread.