Peanut Butter Blondies

For brownies
2 sticks (1/2 pound) unsalted butter, softened
1 3/4 cups sugar
1 cup creamy peanut butter
2 large eggs plus 1 large yolk
2 teaspoons pure vanilla extract
2 cups all-purpose flour
1 1/2 cups semisweet chocolate chips (9 ounces)
1/2 teaspoon salt

For ganache
1 1/2 cups semisweet chocolate chips (9 ounces)
1/2 cup heavy cream
1 tablespoon unsalted butter, softened

Make brownies: Preheat oven to 350 degrees F with rack in middle. Butter a 13- by 9- by 2-inch baking pan, then line bottom of pan with parchment paper and butter parchment.

Beat together butter and sugar with an electric mixer at medium-high speed until mixture is light and fluffy, then add peanut butter and beat until incorporated. Beat in whole eggs, egg yolk, and vanilla. Reduce mixer sped to low, then mix in flour and salt until just combined.

Mix in chocolate chips (1 1/2 cups) then spread batter in baking pan, smoothing top. (It will be thick, almost like cookie batter.)

Bake until brownies are deep golden, puffed on top and a wooden pick inserted in center come out with some crumbs adhering, 40 to 45 minutes.

Cool completely in pan on a rack, about 1 1/2 hours.

Make ganache: Put chocolate chips (1 1/2 cups) in a heatproof bowl.

Bring cream to a boil in a small saucepan, then pour over chocolate chips and let mixture stand for one minute.

Gently whisk in butter until it is incorporated, chocolate is melted, and a smooth mixture forms.

Spread ganache on cooled brownies and let stand until set, about 15 minutes.

Brownies keep in one layer in an airtight container three days, and we hope much longer if hidden in the back of the freezer.