Preheat your oven to 425˚F (220˚C).
Add oil to a large heavy-bottomed skillet over medium heat. Once the oil is heated, add in the sweet potato rounds and cook for 3-5 minutes, until browned, then flip and cook for another 3-5 minutes.
Lower the heat slightly, and add in the butter. Once melted, add in the garlic, rosemary, and thyme. Cook until the butter is foamy and aromatic, and then use a spoon to baste the infused butter over each of the sweet potato rounds.
Pour in the vegetable broth, then move the skillet to the hot oven and roast for about 40 minutes. The potatoes are done when a knife or fork inserted into one of the potatoes meets no resistance (they should be very soft!). The liquid in the bottom of the pan will also have reduced to almost nothing.
Add butter to another pan over medium low heat. Once melted, add in the brown sugar and stir continuously, until the brown sugar is dissolved. Pour in the heavy cream and stir until the sauce starts to thicken.
Add in the pecans, rosemary, and a pinch of salt, and cook until the mixture thickens slightly, but still runs off a spatula easily (about 3 minutes). Remove from heat, then add in the bourbon carefully (it will bubble aggressively as the alcohol boils off). Stir well.
Transfer the sweet potatoes to a serving platter, cover with sauce, and enjoy!
