Pour half of the oil into a deep skillet over medium-high heat. When hot, add the mushrooms and a pinch of salt and pepper and cook, stirring occasionally, 5-10 minute, until the shiitakes are crisp. USe a slotted spoon to transfer them to a plate and set aside.

Add the remaining oil to the skillet, then the garlic and ginger. After 1 minute, add the eggplant, and cook, stirring about once a minute, until the eggplant browns, 5-10 minutes. Stir in the chile paste (if using) and the vegetable stock. Scrape any bits from the bottom of the pan, and continue to cook until the eggplant is meltingly tender, 10-15 more minutes, adding a little more broth if the pan dries out. Stir in the soy sauce, then add the tofu. Cook, stirring occasionally, for about 5 minutes, until the tofu is hot. Fold in the cooked shiitake mushrooms, and taste and adjust seasoning as needed. Serve hot, with optional garnishes.