His eldest son would soon be off to college, and Cal Peternell was worried. Did his son know how to cook?

That was a question that nibbled at the core of Peternell, who not only prepared food at home but also was a chef at Chez Panisse in Berkeley, Calif. His three sons had often joined him in the kitchen where they pounded garlic, whipped cream or baked cookies.

But had they paid attention to what their father was doing? Or, more important for Peternell, had he explicitly instructed them in the basics? With only a summer to catch up, Peternell got to work sharing his knowledge in a more focused manner with a crash-cooking course for his children.

Not long after his eldest arrived at college, he called his father with a cooking question. Then another. As Peternell offered his culinary advice from afar, he realized he had the makings of a cookbook. “Twelve Recipes” (William Morrow, 288 pages, $26.99) is the charming result, a culinary manual written for beginners, but full of useful chef wisdom that an experienced cook will appreciate, all written in a very conversational tone that makes this book such a pleasure to read. I want to have dinner with Peternell!

Though the title says 12 recipes, there are actually 13 categories of food that Peternell addresses — though two of those chapters are Pasta With Tomato, and Pasta Otherwise, so perhaps it’s really 12. Other topics range from eggs and beans to salad dressings and roasted chicken. But that’s just the beginning, as Peternell takes us far afield with variations aplenty and stories that will keep you turning the page.

This is one of the best cookbooks of the year.

Citrus Zest Vinaigrette

Makes about 1/4 cup.

Note: The California winter brings a sweet confusion of citrus fruits. This vinaigrette can use up a little of all of those grapefruit, kumquat, clementine, Meyer lemon and tangerine rinds if you have them, but it is also remarkably good with just lemon and orange zests. It’s perfect poured over a platter of sliced avocados with peeled and sliced oranges or roasted beets. From “Twelve Recipes,” by Cal Peternell.

1 tsp. zest (lemon, orange, lime, grapefruit, etc.)

1 tbsp. small-diced shallot

2 tsp. lemon or orange juice

1 1/2 tsp. red wine vinegar

1/4 tsp. salt

Freshly ground black pepper

3 tbsp. olive oil

Directions

The citrus zest has to be in very tiny pieces for this dressing, and there are a couple of ways to accomplish this. One is to use a vegetable peeler to cut strips of skin from the fruit, line up the strips and cut them into little sticks, and then line up the sticks and cut them into tiny bits.

Another is to use the smallest holes on the box grater and then go over the gratings with a knife. Or, if you must, use a microplane (which, for the author, creates too feathery an effect —he like little bits, not microbits). Mix the shallot, citrus juice, vinegar, salt and pepper with the zest, and let sit for 5 minutes to marinate the shallot. Stir in the oil.

Other uses: Spoon this dressing over boiled vegetables or grilled or baked fish fillets.