Shirley Corriher and her Tunnel of Fudge cake. ©Robin Nelson

Whether you want to know why a cake, cookie, pie or bread recipe works or just that it will work every time, BakeWise (Scribner, $40) is for you. This long-awaited book by Shirley O. Corriher complements and expands upon the information in CookWise (Morrow, 1997), which won the James Beard Award for Excellence.

Corriher is a scientist who loves to cook. She goes into great detail about ingredients, mixing methods, ovens … all the variables that play a part in the finished product.

If you’re wondering about the roles sugar plays in cakes, for example, check out page 73. (Here’s a summary: It holds moisture, contributes to texture, controls microbial activity, contributes to browning, adds bulk and has complex indirect influences on flavor.) And if you want to experience sugar in action, try this recipe. As Corriher points out:

• Brown sugar makes chocolate taste fudgy
• With this extreme amount of sugar the cake does not fully cook, thus creating the “tunnel of fudge” in the center.

IMPROVED TUNNEL OF FUDGE CAKE

Yield: 1 (12-cup) bundt cake

2 1/2 cups walnut pieces or mixed walnuts and pecans (see note)

1 1/4 cups plus 2 tablespoons unsalted butter, cut into 2-tablespoon pieces, divided

3/4 teaspoon salt, divided

Nonstick cooking spray

1 cup granulated sugar

3/4 cup packed dark brown sugar

1 teaspoon vanilla

1/3 cup canola oil

2 large egg yolks

2 cups powdered sugar, plus more for optional garnish

3/4 cup natural cocoa powder (Corriher’s favorites are Ghirardelli and Scharffen Berger)

4 large eggs

2 1/4 cups spooned and leveled bleached all-purpose flour

Rum Drizzle, optional (see note)

1. Arrange a shelf in lower third of oven, place a baking stone on shelf, and preheat oven to 350 degrees.

2. On a large baking sheet, roast nuts for 10 minutes. Pour into a bowl, add 2 tablespoons butter and 1/4 teaspoon salt, and toss well. When cool, chop coarsely and set aside.

3. Spray a 12-cup bundt pan generously with nonstick cooking spray.

4. With a mixer, beat remaining 1 1/4 cups butter to soften and get to the fluffy stage. Add granulated sugar, then brown sugar, and continue to beat until light and airy. While beating, feel the bowl; if it does not feel cool, place in the freezer for 5 minutes, then continue beating.

5. Beat in remaining 1/2  teaspoon salt and vanilla. Blend in oil and egg yolks.

6. By hand, stir in powdered sugar, then cocoa powder.

7. By hand, one at a time, stir eggs into batter, with minimum stirring just to blend them into the batter well.

8. In a large mixing bowl, stir together flour and nuts. Fold into batter; pour into the prepared pan. (Atlanta wine expert Gil Kulers, who makes this cake frequently, heats the empty pan for about 5 minutes before he pours in the batter. This ensures that he gets a good 3/4 inch of well-set cake to hold the fudge center.)

9. Bake for 45 minutes. (You can’t test for doneness because of the fudgy center.)

10. When you remove the cake from the oven, it will have a runny fudge core with an air pocket above the fudge. The air pocket is not desirable and will become a hole under the fudge when the cake is chilled. To minimize this air pocket, about 20 minutes after you take the cake from the oven, while still in the pan, press down on the inside and outside edges of the cake bottom all the way around. Leave the cake in the pan on a rack until completely cooled, 2 to 3 hours.

11. With a thin knife, loosen the cooled cake around the edges. Place a platter on top of the pan and invert. Lift the pan off the cake.

12. Sprinkle with powdered sugar (Corriher’s favorite) or drizzle with Rum Drizzle. Serve at room temperature or cold. At room temperature, the fudge is runny. When cold, the fudge center becomes firm, like a piece of fudge with nuts.

Notes: Don’t leave out the nuts. “Without them, the cake seeems ordinary, but with them, it’s fantastic,” Corriher writes.

To make Rum Drizzle, stir together 1 cup powdered sugar, 1 teaspoon vanilla and 1/2 teaspoon rum (or brandy, for Brandy Drizzle). Add about 2 tablespoons heavy cream, mixing to a consistency that will give you a thick drizzle.