1Slice the cabbage vertically into 4 (1-inch-thick) steaks.
2Brush the tops of the cabbage steaks with the oil mixture.
3Sprinkle with oregano and pepper.
4Roast, rotating the pan from front to back and flipping the cabbage halfway through, until browned and tender, about 40 minutes. Sprinkle with salt.
5Add scallion whites; cook, stirring often, until softened, about 1 minute.
6Add spinach, in batches; cook, stirring constantly, until wilted.
7Stir in dill, parsley, lemon zest, scallion greens and the remaining garlic and pepper. Cook, stirring constantly, until the garlic is fragrant, about 1 minute.
8Transfer the mixture to a medium mixing bowl. Stir in ricotta and feta.
9Spoon spinach mixture on top of each cabbage steak and top each with Cheddar.
10Broil until the cheese melts and starts to lightly brown.