In a large pot, bring 2 cups of dry split peas and 6 cups of water to a full boil. Add the sage and salt. Reduce the heat to a simmer and cook covered for 40-50 minutes, until peas are soft, soup is thickened and creamy.

Preheat the oven to 400 degrees. Cut the eggplants in half lengthwise, drizzle 2 tablespoons of olive oil and some salt on the flesh. Place the eggplants skin-side up on a baking sheet. Bake for 30 minutes or until the flesh is very soft.

While the eggplant is roasting and split peas are cooking, sauté the onion in 1 tablespoon of olive oil until soft and browned, about 15 minutes.

Add the cooked split peas to a blender and blend until creamy. Transfer the split peas back into the large pot.

Scoop the eggplant flesh into the blender and discard the skin. Add the sautéed onion and a cup of the vegetable broth in with the eggplant and blend until smooth.

Transfer the eggplant mixture into the large pot with the split peas. Add the remaining vegetable stock, bring to a gentle boil and remove from heat. Serve with shredded cheese on top.