In a small saucepan, bring the vegetable broth to a low simmer and keep it warm on the back burner.
Heat the olive oil in a large deep skillet over medium heat; add the sliced cremini mushrooms and chopped artichoke hearts, sautéing until they are golden brown and tender.
Remove the mushrooms and artichokes from the skillet and set them aside on a plate.
In the same skillet, add the diced yellow onion and minced garlic, sautéing for 2-3 minutes until the onion becomes translucent.
Crumble the tempeh into very small, rice-sized pieces using your hands or a fork, then add it to the skillet and cook for 4 minutes until lightly browned.
Add the arborio rice to the skillet, stirring constantly for 1 minute to toast the grains until the edges look slightly translucent.
Add the warm vegetable broth to the rice mixture one ladle at a time, stirring frequently and waiting for the liquid to be fully absorbed before adding the next ladle.
Continue this process for about 18-20 minutes until the rice is al dente and the consistency is naturally creamy.
Stir in the nutritional yeast, lemon juice, sea salt, and black pepper to create a savory, cheesy flavor profile.
Fold the cooked mushrooms and artichokes back into the risotto and stir gently to combine.
Garnish with freshly chopped parsley and serve immediately while hot.