Method:

Preheat oven to 350F

Peel the yam and cut into slices about 1/2" thick. Stream or microwave yam slices until just tender (about 10 minutes on high in a microwave). While yams are cooking use a zester to remove the zest from the lime and chop very fine. If you don't have a zester then use a very sharp paring knife to remove the rind and cut off all the white pith. After zesting the lime cut in half and squeeze out the juice, retain the juce. You only want the green part of the skin. Peel the ginger root and grate very fine.

When yams are tender transfer them to a mixing bowl or food processor, add butter, and mix until smooth. Add lime zest, jusice, salt and pepper to taste. It is important that you taste the mixture as you go along. You want to keep the flavours somewhat subtle, that is you still want to be able to taste the yam. Now add 1/2 the grated ginger and taste again, keep adding ginger until you are satified with the amount - this is a personal preference. Add Teriyaki sauce 1 tablespoon at a time until you can just taste it in the background. Mixture should be no looser than mashed potatoes. It should hold a peak.

If using fresh spinach then steam it until willted then drain it, if using packaged frozen spinach then thaw the spinach, draine it, and proceed. Season spinach with fresh ground nutmeg, salt and pepper. Again, the seasoning should be subtle not overwhelming and keep in mind you have already salted the the yam mixture.

Place tart shells on a baking sheet. Add spinach to each tart shell. Press spinach down to form a packed layer that fills the shell 1/4 full. Place yam mixture in a piping bag and using a large rossette tube fill the tarts . If you don't have a piping bag then just use a spoon.

Bake at 350F just until the tops of the tart shells turn a nice golden brown - about 12 minutes.

Remove from oven and top with a twist of sweet pickled ginger. Serve warm or cold.