One of the things I look forward to about spring is picking fresh nasturtium leaves and flowers for salads, sandwiches and mayonnaise. These peppery little leaves grow in great profusion on banks and sidewalks here in Hout Bay, and I have no compunction about filling bags with them because they're not native to South Africa, and no one else seems to want to eat them.
egg and fennel salad, but I've never made any other sort of sauce with them. The idea of a pesto occurred to me in the middle of the night (I often think about recipes in the wee hours) but I wasn't convinced it would work. Although nasturtium leaves have a powerful flavour - at least as pungent as that of basil - I didn't know how they'd taste with garlic, and the idea of combining them with resiny pine nuts didn't appeal at all. So, when formulating the recipe, I used buttery, meek-flavoured macadamia nuts to tone down the pepperiness, and a modest single clove of garlic. The result was a thick pesto of a glorious pistachio green, with an intriguing flavour and a satisfying zing. I did find, however, that much of the pepperiness had faded by this morning, and that the olive oil, garlic and Parmesan flavours had pushed their way to the front. So this is a pesto for making in smallish quantities and serving immediately.
I almost always make pestos in the old chemists' mortar that once belonged to my grandfather, but you can whizz this all up in a food processor or the jug attachment to a stick blender. Take care not to over-process it, however, or the nuts will become greasy and the pesto will lose its interesting texture.
Nasturtium & Macadamia Nut Pesto
1 cup (250 ml) whole unsalted macadamia nuts
1 clove garlic, peeled
a small pinch of flaky sea salt
2 cups (500 ml), fairly closely packed, fresh young nasturtium leaves and their stalks
8 Tbsp (120 ml) extra-virgin olive oil
30 g Parmesan, finely grated
the juice of half a lemon, or more, to taste
3 nasturtium flowers (for colour)
Put the nuts, garlic and salt into a mortar and pound until you have a coarse paste. Add the nasturtium leaves and continue pounding until you have a thick, slightly gritty paste. Add the olive oil tablespoon by tablespoon - you may not need to use it all - until the pesto is the desired consistency. Stir in the Parmesan and lemon juice (to taste) and season with salt. As the Parmesan is already salty, go easy! You won't need to add any pepper.
Finely chop the nasturtium flowers and stir them into the pesto. Use within 8 hours for best results. It will still taste good the next day, but the peppery flavour will have receded somewhat (see my notes above).
Makes about 1½ cups.