Set oven to 420F/216C.
Chop the head off a garlic bulb, then spray or drizzle olive oil on top of it with a pinch of sea salt. Wrap the bulb in foil then place in the oven for 25 – 30 minutes. After roasting, set aside to let it cool down.
In a pot of cold or room temperature water, add the potatoes and florets. Add a pinch of sea salt, then bring the water to a boil and cook until the veggies are fork tender, around 25 minutes.
Drain the pot VERY WELL – try to remove as much liquid as possible – then place a towel on top of the pot to absorb and catch steam. This will help prevent a watery mash. Mash up everything in the pot using a masher or fork (or immersion blender). Add butter, chives, yogurt and roasted garlic and mix everything together using a spoon. Season to taste with sea salt & pepper.