-
1
Peel the potatoes, then cut them into very fine slices.
-
2
A sharp knife is fine but if you have a mandoline (the vegetable slicer, that is, not the lutelike stringed instrument), use that.
-
3
Whatever, your slices should be almost thin enough to see through.
-
4
Do the same with the rutabaga, keeping the slices in cold water to prevent them browning.
-
5
Preheat the oven to 375F (190C).
-
6
Peel and thinly slice the garlic.
-
7
Over medium heat, melt the butter in a flameproof dish or saute pan about 10 inches (25cm) in diameter.
-
8
When it starts to bubble, decrease the heat and add the garlic.
-
9
It needs to soften slightly without coloringa matter of five minutes or so.
-
10
Take the pan off the heat and stir in the mustard.
-
11
Remove about two-thirds of the mustard and butter out of the pan and into a pitcher.
-
12
Drain the potato and rutabaga slices and pat them dry with paper towels or a clean kitchen towel.
-
13
Put a third of the vegetables into the pan, layering them neatly or just chucking them in as the mood takes you, then drizzle them with some of the mustard butter in the pitcher.
-
14
Season with the thyme leaves, pepper, and salt.
-
15
Be quite generous with the salt.
-
16
Repeat this twice, so that all the slices of vegetable are layered with the thyme and the mustard and garlic butter.
-
17
Now pour the stock over the top.
-
18
Cover with a circle of wax paper or aluminum foil, pressing it down well on top of the cake.
-
19
Bake for about an hour and ten minutes, until tender when pierced with the tip of a knife.
-
20
Remove the foil, increase the heat to 425F (220C), and bake for a further ten minutes, until the top has colored and crisped a little.
