Cauliflower Bisque with Lemon Thyme Oil

While cauliflower is roasting, to medium saucepan, add potatoes, garlic, thyme sprig, and 2 cups (500 mL) cold water. Set on medium heat and bring to gentle simmer. Once contents begin to simmer, cook, uncovered, for approximately 30 minutes, or until potatoes are fork tender, reducing heat if necessary to keep contents at a low simmer.