Heat oven to 190C/170C fan/gas 5.
Tip the cream, milk and garlic into a large
saucepan and bring to a simmer. Slice the
potatoes very finely, about 3-4mm, add
them to the cream and simmer for 3 mins
until just cooked. Gently stir to separate
the potato and stop it sinking and
catching on the bottom of the pan.
Remove the potatoes with a slotted
spoon and place in a wide shallow
ovenproof dish so that they are about
5cm in depth. Pour over the garlic infused
cream (discarding the garlic) – just enough
to seep through the layers and leave a
little moisture on the surface. Scatter
over the cheese, if using, then bake for
30 mins until the potatoes are soft and
browned – increase the heat for 5 mins
if not brown enough.