Add the chicken stock (or vegetable broth/water) to a medium saucepan and set over medium-high heat. Bring to a simmer, reduce heat to low, cover, and set aside to keep warm.
Melt the butter in a large, heavy-bottomed saucepan over medium heat. Add the onions and sauté for 5-7 minutes, or until the onions are soft and translucent.
Add rice and salt and mix thoroughly with the onions. Cook for 1-2 minutes, or just long enough to allow the rice to turn fragrant. Careful not to brown the rice.
Increase heat to medium to medium-high. Add a ladle (approximately 1/2 cup) of hot chicken stock to the rice. Stir until the liquid is fully absorbed. When nearly all the liquid is absorbed, stir in an additional ladle of hot chicken broth.
Continue adding chicken stock, one ladle at a time. Stir between each addition and wait to add the next ladle until the stock has been absorbed. This process will take anywhere between 20-30 minutes. Continue until the grains are al dente, or tender, yet firm.
Season or garnish with additional butter, Parmesan cheese, or fresh herbs.