At least 4 hours in advance, and preferably the night before, make the ramen eggs. Bring water just to a boil in a medium-large saucepan. You need enough water to submerge your eggs by at least 1 inch.
Carefully add your cold eggs to the pot. Let eggs boil for 7 minutes exactly, adjusting the temperature as necessary to make sure that the eggs don’t crack against each other.
Prepare a large bowl of cold water with ice.
While eggs are cooking, prepare the marinade. Combine soy sauce, mirin, and water in a ziploc baggie. I find it easiest to put the baggie into a glass while you are filling it, so that it doesn’t tip over and spill everywhere.
After 7 minutes of cooking, transfer the eggs to the ice bath and let cool for 3 minutes. (Try not to wait longer than this, as eggs are easier to peel if you peel them quickly after boiling.)
Peel carefully, as eggs are softer than traditional hard-boiled eggs. When they are peeled, transfer to the baggie with the marinade and refrigerate for 4 hours or up to 24 hours.
To continue with the rest of the recipe, preheat oven to 400.
Line a baking sheet with parchment paper.
Peel sweet potato and cut into ¾ inch cubes.
Toss sweet potato with 1 tablespoon olive oil, ¼ teaspoon salt, and ¼ teaspoon pepper, and spread out on sheet pan.
Bake for 20 minutes, stir cubes with a plastic spatula, and move to one side of the pan.
Meanwhile, toss 6 ounces of baby spinach with ½ tablespoon olive oil, a pinch of salt, and a pinch of pepper.
After you move the sweet potatoes to one side of the pan, mound the spinach on the other side. If your pan is too crowded, feel free to use two pans.
Continue baking until the sweet potatoes are tender and lightly browned, and spinach is wilted (about 5-10 more minutes).
Meanwhile, make the rice. Bring 1 ½ cups of water to boil in a small saucepan with a lid.
Stir in 1 cup of rice and ½ teaspoon salt. When rice comes back to a boil, turn down the heat to low, and cover with lid.
Simmer for 15-20 minutes until water evaporates, and rice is tender.
Now, make the sauce for the rice bowl. Whisk together sesame oil, soy sauce, maple syrup, rice vinegar, and crushed red pepper in a small bowl.
To serve, spoon rice into your bowl and top with sweet potatoes, spinach, and a ramen egg, sliced in half. Drizzle with sauce and sprinkle with furikake, if desired.
Notes
Ramen egg recipe adapted from savorysimple.netFor the ramen eggs, you can cook the eggs for 8-9 minutes instead of 7 if you prefer your eggs less runny. Note that after 24 hours, they should be removed from the marinade and the marinade should be discarded. The ramen eggs will keep in the refrigerator in a sealed container for another 2 days.