Preheat the oven to 400 degrees Fahrenheit. Slice the eggplant in half lengthwise and place on a foil- or parchment-lined baking sheet. Bake for 35-45 minutes, or until the peel is somewhat blistered and the flesh is very soft. Once cool enough to handle, scoop out the eggplant flesh and finely chop it. My eggplant yielded about 4.5 cups after roasting.
In a large bowl, combine the rice with 4 cups of vegetable stock, and stir it vigorously to wash the starch out of the rice. Pour into a colander, making sure to reserve the starchy broth - this is the liquid that will be used for cooking the risotto. Let the rice drain in the colander for 5-10 minutes.
In a large saucepan, heat olive oil over medium heat until shimmering. Add the chopped onion and a pinch of salt and cook, stirring occasionally, until the onion is softened, about 5 minutes. Stir in the minced garlic and cook for about 1 more minute until fragrant.
Add the oregano and pepper and 1 cup of the reserved vegetable stock and stir. Thereafter, stir the risotto frequently and add 1/2 cup of stock whenever the liquid is absorbed. Stop adding it once the rice is al dente (cooked through, but with a slight bite or chew to it). You may need additional vegetable stock beyond what you used for rinsing the rice.
I used an additional 1.5 cups of vegetable broth during cooking. Use a broth or stock that you like; the rice will absorb a lot of its flavor.
I particularly like to use Sauvignon Blanc wine in risotto. Note that the finished product will have a notable wine flavor, though most of the alcohol will cook off. If you prefer more of a gentle wine flavor, or are concerned about alcohol content, feel free to reduce the wine to 2/3 or 1/2 cup. My motto for cooking wine is that if I wouldn't enjoy drinking it, I won't enjoy tasting it in my food.
For alternatives to coconut milk, try finishing the risotto with cashew cream or a pat of your favorite vegan butter.
The step of washing the starch out of the rice is optional, but I find that taking this step yields a risotto with the best balance of creaminess and nutty flavor.