Cook the quinoa according to the instructions and until it’s light and fluffy
As the quinoa is cooking and cooling, finely dice the tomatoes and cucumbers, put them in a bowl, and set aside to sit for at least 10 minutes
In a food processor or by hand, finely chop the parsley
Fold the parsley and any of the optional ingredients into the cooked quinoa
Drain the excess juice that accumulated at the bottom of the bowl of vegetables (so it won’t make the quinoa soggy), then fold into the quinoa
In a bowl, combine the lemon juice (juice it directly into the bowl if using fresh), oil, sea salt, and black pepper, pour over the quinoa, and mix together
Tabbouli is served cold, so let it chill in the fridge for at least 1 hour before eating