Rinse the basmati rice under cold water until the water runs clear.
In a large pot, heat the olive oil over medium heat.
Add the chopped onion and sauté until translucent, about 5 minutes.
Stir in the minced garlic and cumin seeds, cooking for an additional minute.
Add the rinsed rice to the pot, stirring to coat the grains with oil.
Pour in the broth and add the bay leaf, salt, and pepper.
Bring the mixture to a boil, then reduce heat to low, cover, and simmer for 15 minutes.
If using, add diced vegetables halfway through cooking.
Remove from heat and let sit covered for another 5 minutes.
Fluff the rice with a fork, garnish with fresh parsley, and serve warm.