Place the beef broth on the stove on low heat to keep warm.
In a wide pot on medium-low heat melt the butter. Once melted add the garlic and thyme leaves, and approx. 1/2 tsp of salt. Cook for 1-2 minutes until fragrant and soft. The garlic should not be brown, at any point it starts to brown lower the heat.
Add arborio rice and mix to combine. Toast rice for 3-4 minutes until it starts to become translucent.
Pour in the wine and stir. Cook for 3-4 minutes until the wine is almost non existent.
Add the onions and mix to combine.
Add the first round of broth. Depending on the pan add broth until it just covers the risotto. (could be 1 cup to 1 1/2 cups). Give it a quick mix, a shake of the pan to ensure all grains are covered and cook until rice absorbs the majority of the broth. Mix 2-3 times each round of broth. Don't worry if you mix more. It terms of seasoning after the first round taste it (avoiding the rice), if it needs salt start with a heavy pinch (1/4 tsp) and go from there.
Add more broth and repeat above steps. This recipe calls between 4-5 cups of broth. If you notice that it is perfectly cooked at 4, don't add more. This part of the recipe really takes intuition and feeling, if the rice is still hard or hard for your liking then add more little by little.
Once all broth has been added, but not completely absorbed (15-18 minutes of cooking) give it a taste. The rice should be loose, yet al dente. If the rice has too much of a bite add more broth, about 1/4 cup at a time. Once al dente add the Parmesan cheese. Mix to incorporate. Serve immediately.