MY GO-TO dessert when baking for someone avoiding gluten has always been a nut torte. This type of flourless cake gets its structure from nut flours and eggs, and takes very well to chocolate. But one recent day, with a bag of freshly picked apples and a gluten-sensitive dinner guest on the way, I decided to brave a gluten-free galette. While most recipes simply call for substituting wheat flour with a wheat-free flour blend, I sensed that this approach would yield limited success.

I called Katarina Cermelj, a Ph.D. in inorganic...

MY GO-TO dessert when baking for someone avoiding gluten has always been a nut torte. This type of flourless cake gets its structure from nut flours and eggs, and takes very well to chocolate. But one recent day, with a bag of freshly picked apples and a gluten-sensitive dinner guest on the way, I decided to brave a gluten-free galette. While most recipes simply call for substituting wheat flour with a wheat-free flour blend, I sensed that this approach would yield limited success.

SHARE YOUR THOUGHTS

Share your experience with these recipes. Did you make any adaptations? How did you serve it? Join the conversation below.

I called Katarina Cermelj, a Ph.D. in inorganic chemistry and the author of “Baked to Perfection: Delicious Gluten-Free Recipes With a Pinch of Science,” for advice. The subject of our call quickly became xanthan gum, a binder that gives gluten-free recipes the elasticity and flexibility the gluten in wheat flour would otherwise provide. Dr. Cermelj suggested I add a pinch of the gum—sold as a powder—to water. A gel formed instantly, illustrating why it’s called gum. This experiment was also her way of warning me that a little goes a long way. That night, xanthan gum saved my galette dough from being dry and crumbly. The flaky crust proved so good, in fact, that I used it the following day for a pissaladière, the Provençal onion tart.

With a little further research, I came to understand that xanthan gum is a type of carbohydrate known as a polysaccharide, useful to cooks because it is a uniquely efficient stabilizer that, unlike other starches, requires no heat to hydrate. Browsing the gluten-free-flour selection at my local supermarket was, however, confusing enough to send me to back to Dr. Cermelj for another lesson.

Find the recipe for this lemon drizzle cake below.

Photo: Ted + Chelsea Cavanaugh FOR THE WALL STREET JOURNAL, FOOD STYLING BY PEARL JONES, PROP STYLING BY BETH PAKRADOONI

She explained that no two blends are the same, and she recommended checking the ingredient list. Some gluten-free flours already contain a small amount of xanthan gum, and if that’s the case, you should reduce the amount of xanthan you add, generally by half. If you can, buy a blend without any xanthan so you can better control the ratio.

Dr. Cermelj also urged that flour blends be weighed by scale, not measured by cup—and there she was preaching to the converted. While it typically works fine to measure conventional flour by fluffing with a fork, spooning lightly into a measuring cup and running the flat-side of a knife across the top to remove excess, I had already found that measuring gluten-free blends this way produces results that vary in weight by as much as 40%. For accuracy, it’s worth weighing your gluten-free flour on a scale. (The recipes accompanying this story give flour measurements in both grams and cups.)

No wonder chemists are drawn to baking. Making a cake rise and producing a tender crumb—in other words, achieving the right structure—demands precision when it comes to the flour, eggs, fat and leavener. Armed with my scale and my xanthan gum, I made easy work of Dr. Cermelj’s recipe for chocolate marble Bundt cake with a sunny citrus edge. I’ve added it to my gluten-free holiday-baking repertoire along with that apple galette, plus a classic lemon drizzle cake and some delicious peanut butter and jam thumbprint cookies worth including in any Christmastime tin.

To explore and search through all our recipes, check out the new WSJ Recipes page.