Heat oven to 200 C / 400 F. Slice the top off the garlic head to expose the cloves, drizzle with 1 tsp olive oil, and wrap tightly in foil on a small sheet pan.

Roast for 35 to 40 minutes until the cloves are soft, golden, and easily pierced with a knife. Cool for 10 minutes, then squeeze the cloves from their skins into a small bowl and mash with a fork.

Meanwhile, place the potato chunks in a 3-quart saucepan, cover with cold water by 2.5 cm / 1 inch, add a pinch of salt, and bring to a boil. Simmer 12 to 15 minutes until fork-tender.

Drain well and return the potatoes to the hot, empty saucepan for 1 minute to steam off excess moisture. This keeps the cakes from turning gummy later.

Mash the potatoes with a potato masher until mostly smooth. Add the butter, warm milk, roasted garlic, parmesan, chives, salt, and pepper, and mix until combined. Let cool for 10 minutes, then stir in the egg.

Cover and chill the mash in the fridge for at least 30 minutes, or up to overnight, until firm enough to shape. This step is what keeps the cakes from falling apart in the skillet.

Scoop about 1/2 cup (roughly 140 g) of mash per cake and shape into 8 patties, about 8 cm / 3 inches wide and 2 cm / 3/4 inch thick.

Spread the panko on a plate and press each patty into the crumbs, coating both sides firmly.

Heat 1.5 tbsp olive oil in a 12-inch nonstick skillet over medium heat. Fry the cakes in two batches of 4 so they have room to crisp, cooking 4 to 5 minutes per side until deep golden brown. Add the remaining 1.5 tbsp oil before the second batch.

Transfer to a paper-towel-lined plate briefly to drain, then serve warm.