Basil Pesto Freezer Cubes

From the garden

• 6 cups fresh basil leaves, packed, washed and dried very well
• 3 cloves garlic
• ½ cup walnuts or pine nuts, lightly toasted

From the pantry

• 1 cup olive oil · plus a little extra for topping the cubes
• ¾ cup finely grated parmesan (optional) · classic, but many cooks freeze the pesto without cheese and stir it in fresh after thawing
• salt · to taste

1. Wash the basil and dry it completely in a salad spinner and on towels. Clinging water makes icy, dull cubes. Toast the nuts in a dry skillet over medium heat, tossing, 3–4 minutes until fragrant, and let them cool.
2. Pulse the garlic and nuts in a food processor until finely chopped. Add the basil and a good pinch of salt and pulse in short bursts, scraping down the sides, until finely chopped but still bright green, not a purée.
3. Pulse in the olive oil in two or three additions until the pesto is spoonable but still has texture. Stir in the parmesan, if using, and season. It should taste bold and a touch too salty straight, since freezing mutes flavor slightly.
4. Spoon the pesto into two ice-cube trays, pressing it into the corners, and slick the top of each cube with a thin film of olive oil to keep the surface green.
5. Freeze until solid, at least 6 hours, then pop the cubes into a freezer bag, press out the air, and label. Each cube is about 2 tablespoons; two or three sauces a serving of pasta.