01 -
Warm up your oven to 200°C. Smear the soft butter all over a 3-quart baking dish.
02 -
Grab a mandoline for even results and cut your sweet potatoes, parsnips, and beets into super thin circles. Put each veggie in its own bowl.
03 -
Drizzle 4 tbsp cream on the sweet potatoes and parsnips, and just 2 tbsp on the beets. Add ½ ounce Parmesan and 1 tsp thyme to each bowl. Throw in lots of salt and pepper, then mix until everything's coated.
04 -
Pour what's left of your cream (about 60ml) into the buttered dish. Scatter ½ ounce Parmesan and all the minced garlic on top.
05 -
Stand your veggie slices upright in rows, going sweet potatoes first, then parsnips, followed by beets. Keep this pattern going until you've used everything up, making about 6 rows.
06 -
Sprinkle more salt and pepper on top, then add the remaining Parmesan.
07 -
Cover with foil and pop in the oven for 30 minutes or until the veggies start getting soft.
08 -
Take off the foil and sprinkle all the shredded Gruyère evenly across the top.
09 -
Put it back in the oven uncovered for another 18-20 minutes until you can easily stick a fork in the veggies, the cheese has melted, and the top looks slightly brown.
10 -
Sprinkle some fresh thyme leaves on top before bringing it to the table.