Set the rice to cook while you prepare the vegetables (or you can prepare it ahead, depending how serving - see above). Set aside once ready.
Bring a small-medium pot of water to a boil and add the beansprouts. Simmer for a couple minutes until they are going slightly translucent but still have a crunch to them.
Drain the beansprouts from the pot, saving the water, then either pour the hot water over the spinach in a bowl, or put the spinach in the pot. Either way, wilt the spinach (it will just take a minute) then drain the spinach. Set aside to cool. Meanwhile, dress the beansprouts with the sesame oil, garlic powder and salt and top with the sesame seeds.
Once the spinach has cooled enough to handle, squeeze it well to remove excess water then thinly shred it. Dress with the sesame oil, garlic powder and salt and top with the sesame seeds.
Cut the cucmber into thin battons (julienne), toss with salt then after a couple minutes, squeeze any excess water from it.
Cut the carrots in thin battons (julienne), remove the stems from the mushrooms and slice them. Warm the oil in a small skillet and cook the carrots a minute or two to soften. Set aside then cook the mushrooms a minute or two until gently softened.
If serving as dolsot version, warm a little oil in two small-medium skillets/frying pans (ideally cast iron), then add half the cooked rice to each. Warm a few minutes then top with piles of the different vegetables (apart from cucumber), dividing each evenly between the two. Add an egg on top of each, add the cucumber, some gochujang sauce and top with some seaweed. Serve in the pan, mixing the egg through with everything else so the egg cooks in the heat of the pan. Note for this version, all components can be prepared ahead and stored in the fridge.
If you prefer a more 'normal' bowl, add the warm rice to two bowls, top each with half of each of the vegetables (all warm, apart from cucumber), some gochujang sauce and seaweed. Optionally top with a fried egg.