The measurements are not exact, but should do fine for one serving!
Preheat oven to 350 F and start some water boiling. Cut the top off the bell pepper and pull out the seeds and put into boiling water. Save the lid! Make sure to keep an eye on your pepper. You want it to boil so that it's nice and soft, but not so soft that it won't stand up or hold together when you stuff it. I always make stuffed peppers when I have leftover rice because it's easier, but if you prefer fresh rice you should prepare it now!
Heat up a pan and dice all veggies (except spinach!) and crush the hazelnuts. I usually just smash the hazelnuts with the back of a spoon so they're still in pretty big chunks. Put your half can of diced tomatoes into the pan, make sure you get lots of juice in there too! Drop in the rest of your veggies and spinach and let simmer on low for about 5 minutes. Add rice and a little more tomato juice if needed. Add hazelnuts, pepper, cinnamon, and agave nectar. You want just enough agave to give it a hint of sweetness but not overpower it! Cook on low heat for about five minutes. Take out your cooked bell pepper and set on baking tray. Stuff full of your mushroom and ricey goodness, put the lid on and pop it in the oven for about 10 minutes. You can also leave the lid off and instead top with some vegan cheese for an even yummier pepper.
Don't eat the lid when you take out your pepper! Enjoy!