Bring a large pot or Dutch oven of heavily salted water to a boil and cook orzo until al dente. 1 minute before the orzo is done cooking, add the kale and submerge with a wooden spoon to wilt. Drain and wipe out pot.
Meanwhile, prep the lemon. Rinse the lemon under cold water and cut into thin slices, removing any seeds. Finely chop the slices, zest and pith included.
Make the breadcrumbs. Melt 2 tablespoons butter over medium heat. Add breadcrumbs and cook until golden brown, 3 minutes. Remove from heat and add grated garlic and mix to combine. Season with salt and pepper to taste. Transfer to a small bowl and wipe out pot.
Make the caramelized lemon butter. In reserved pot, melt remaining 4 tablespoons butter over medium heat. Add chopped lemon and cook until fragrant and lightly softened, 5 minutes. Season with salt.
Remove from heat and add cooked orzo and kale and Parmesan, tossing to coat in the caramelized lemon butter. Season to taste with salt and pepper. Serve immediately in bowls with toasted breadcrumbs.