The chocolate cake looked like it was going to make it. The batter was rising nicely in the oven, and then, it dropped in the middle like a sinkhole.

Here was a cake I baked so frequently, I didn’t need to look at a recipe. Ah, but that was at sea level. I was now living in the high desert of Taos, at 7,000 feet.

That meant, I discovered, I had to contend with a drier atmosphere, lower boiling points, and a quicker expansion by such leavening ingredients as baking powder, soda, and yeast. Baking, after all, is often science.

I did all right by reducing the leavening agents a little and sticking to pies and crisps instead of cakes. But then, my daughter, Sarah, sent me the cookbook, Pie in the Sky — Successful Baking at High Altitudes by Susan G. Purdy. Now, my guesswork was eliminated.

The hard-cover book is filled with useful information and recipes for baked goods from muffins to soufflés. Purdy, bless her heart, adjusts each recipe’s ingredients and instructions for kitchens at sea level, 3,000, 5,000, 7,000 and 10,000 feet. How? She tested each recipe at those elevations.

So for Anna’s Butter Cake, bakers at sea level will use 1 teaspoon of baking powder, but at 3,000 feet, 1 1/4 teaspoons. Likewise bakers should adjust the sugar from 1 1/2 cups to 1 1/3 cups.

She also recommends using parchment paper besides greasing and flouring a baking pan. It works. (My one gripe: I wish parchment paper came in circles that fit baking pans instead of rolled sheets.)

Any recipe I’ve tried from this cookbook has been a success. You can tell the ones I like the most by the pages stained with batter. Here are a few: the Daredevil’s Food Cake with Mocha Buttercream Icing; the Chocolate Buttermilk Cake with Bittersweet Chocolate Icing; and the Classic 1-2-3-4 Cake. I even made them at sea level when visiting family this spring.

Her lemon meringue pie while labor-intensive is the best I ever made — or ate.

You can find Pie in the Sky at book stores, cooking supply shops and online at the usual sources.