In salted boiling water, lower a bag of rice. Simmer for 15 minutes. At the end of cooking, take out the bag and let the water drain.
Fry the cashew nuts in a dry pan, stirring, until they have a characteristic smell and golden color, about 3 minutes.
Make the pesto.
Grind the nuts, arugula, garlic clove, and olive oil in a blender (add the amount of olive oil based on your preferences for taste and consistency).
Cut the mushrooms into slices. Quickly fry in olive oil in a preheated frying pan.
Combine rice, mushrooms, and pesto. Mix well. Adjust the taste with salt and ground black pepper. You can also adjust the amount of pesto, focusing on your taste. For meat eaters, I recommend adding fried bacon and grated parmesan to the dish. If served as a salad, you can fill it with natural yogurt, adding a few drops of lemon juice.