I just received an advance copy of Cookie Swap: Creative Treats to Share Throughout the Year (Gibbs Smith, $19.99, 158 pages), and despite the heat wave, it makes me want to turn on the oven and start baking.

The book is by St. Louisan Julia M. Usher, whose creativity, culinary expertise and artistic ability combine in recipes for cookies that are in turn beautiful, fun and sometimes funny. The recipes are reliable, too — to make sure, she hired members of the St. Louis Culinary Society to test each one.

For a barbecue, Julie has concocted Chocolate-Chai Burgers on Sesame Seed Buns. For Easter, she shows how to make cheesecake-filled birds’ nests topped with candied eggs. The nests are made with kataifi (shredded phyllo dough), and while the result is impressive, the method is impressively easy. The wedding chapter includes Tiers of Joy, stacks of shortbread rounds decorated to look like miniature wedding cakes. Each recipe includes a complexity rating from 1 to 3 and an estimate of how long it takes to prepare.

Another St. Louisan, Steve Adams, took the photos, which are fabulous — and mouthwatering.

The book will be on store shelves Aug. 1. This recipe for S’mores Bars is a sneak peak. (Its complexity is 1 — the easiest — and the time required is 45 minutes.)

Julie writes: “I’ve taken the same campy ingredients in s’mores and turned them into an easy-to-package bar, perfect for tossing into summer picnic baskets.” I think they would be a great treat to tote to a fireworks show as well.

S’MORES BARS
Makes 2 dozen (2-inch) squares

Prep Talk: Allow about 1 hour for the brownies to cool before applying the marshmallow topping; otherwise, the marshmallows will melt and flatten. The brownies will stay fresh longer if kept in the pan, tightly wrapped in foil, and cut just before serving. Store at room temperature up to 1 week.

Graham Cracker Crust:
2¼ cups graham cracker crumbs (15 to 17 crackers, finely ground in a food processor)
¼ cup granulated sugar
2 tablespoons firmly packed light brown sugar
¾ cup (1½ sticks) unsalted butter, melted

Fudge Brownie Filling:
6 ounces premium unsweetened chocolate, chopped
1 cup (2 sticks) plus 2 tablespoons unsalted butter, chopped into tablespoon-size pieces
2½ cups granulated sugar
5 large eggs, lightly beaten
1½ teaspoons pure vanilla extract
1¾ cups all-purpose flour
1½ cups pecan halves, toasted and coarsely chopped (optional, for topping)
4 cups (packed) miniature marshmallows (about 8 ounces, for topping)

1. Line a 10 x 15 x 2-inch glass baking dish (sometimes called a roasting pan) with foil, leaving a 1-inch overhang around the top edge of the pan. Smooth out any big wrinkles in the foil and then lightly coat the foil with nonstick cooking spray.

2. Position a rack in the center of the oven and preheat the oven to 350 degrees F.

3. Prepare the Graham Cracker Crust. Combine the graham cracker crumbs and sugars in a small bowl. Gradually add the melted butter until the crumbs just hold together when squeezed in your palm. (The crumbs may absorb slightly more or less butter depending on the graham cracker brand.) Press the mixture into an even ¼-inch-thick layer on the bottom of the prepared pan. Run a smooth-bottomed measuring cup over the crust to pack and level it.

4. Mix the Fudge Brownie Filling. Combine the chocolate and butter in a large bowl (about 4-quart capacity) that fits a double boiler. Place the bowl over barely simmering water and stir as needed until the chocolate and butter are melted. Remove from the heat and whisk in the sugar, followed by the beaten eggs and vanilla extract. Stir in the flour, mixing until smooth. Pour the batter on top of the graham cracker crust and level with a small offset spatula.

5. Top and bake. Scatter the chopped nuts evenly over the batter, if desired. Bake 30 to 35 minutes, or until a cake tester inserted in the brownie center comes out with dark, damp crumbs on it. Do not overbake. Set on a wire rack and cool completely in the pan.

6. Distribute the marshmallows evenly over the brownie top. Place the pan under the broiler in the top third of the oven for about 1 minute, or until the marshmallows are puffy and golden brown. Watch carefully and rotate the pan regularly, as the marshmallows can easily burn. Cool until the topping is firm and easily cut without sticking.

7. Remove the brownies from the pan in one block by gently pulling up on the foil overhang or by easing the block out with an offset spatula. Place directly on a cutting board. Remove all foil and trim any uneven edges before cutting into 2-inch squares. For the neatest cuts, use a sharp knife, wiped clean with a warm, damp cloth between slices.