Ingredients
1 stick plus 6 tablespoons unsalted butter, room temperature, plus more for pan
1 3/4 cups unbleached all-purpose flour
1 teaspoon baking powder
3/4 teaspoon kosher salt
1 1/3 cups packed light-brown sugar
1/3 cup granulated sugar
2 large eggs, room temperature
1 1/3 cups semisweet chocolate chips
2 quarts vanilla ice cream, softened
1/2 cup granulated sugar
3 tablespoons unsalted butter
1/4 teaspoon kosher salt
1/2 cup heavy cream
1 1/2 ounces finely chopped semisweet chocolate (1/3 cup)
Preparation
Blondie:Preheat oven to 350 degrees. Butter a 9-by-13-inch baking pan. Line with parchment, leaving a 2-inch overhang on long sides; butter parchment. Whisk together flour, baking powder, and salt.
Beat butter with both sugars on medium-high speed until light and fluffy, about 2 minutes. Add eggs, one at a time, beating to combine after each addition. Add flour mixture, stirring just until combined (do not overmix). Fold in chocolate chips to evenly incorporate. Scrape batter into prepared pan; smooth top with an offset spatula. Bake until a tester inserted in center comes out clean, 35 to 40 minutes. Let cool completely in pan, then lift out using parchment.
Using the base of an 8-inch springform pan as a guide, cut half of the cake into a round. Cut remaining half into 3/4-inch cubes. (Reserve scraps for snacking.) Place cake round in bottom of springform pan.
Stir 1 1/2 cups cake cubes into softened ice cream, reserving remaining cubes. Spread ice cream over cake in pan. Wrap in plastic and freeze until very firm, at least 6 hours and up to overnight.
Sauce:In a small saucepan, stir together sugar and 3 tablespoons water. Place over low heat until sugar is dissolved. Cover and bring to a steady boil, then uncover and cook, swirling occasionally, until deep amber, 6 to 8 minutes total. Remove from heat; whisk in butter, salt, and cream (it will bubble up). Add chocolate, stirring until just combined. Transfer to a heatproof bowl and refrigerate, stirring occasionally, until mixture is cool and has consistency of thick hot fudge, 30 to 45 minutes.
Remove cake from freezer. Use a sharp knife dipped in warm water and wiped dry to loosen cake from sides of pan, then unlatch and remove. Transfer cake to a serving plate. Pour cooled sauce over top, allowing it to drip down sides. Freeze again, at least 1 hour. Garnish with remaining cake cubes. Slice with a sharp knife dipped in warm water and wiped dry before each cut; serve.
Preheat oven to 350 degrees. Butter a 9-by-13-inch baking pan. Line with parchment, leaving a 2-inch overhang on long sides; butter parchment. Whisk together flour, baking powder, and salt. In a small saucepan, stir together sugar and 3 tablespoons water. Place over low heat until sugar is dissolved. Cover and bring to a steady boil, then uncover and cook, swirling occasionally, until deep amber, 6 to 8 minutes total. Remove from heat; whisk in butter, salt, and cream (it will bubble up). Add chocolate, stirring until just combined. Transfer to a heatproof bowl and refrigerate, stirring occasionally, until mixture is cool and has consistency of thick hot fudge, 30 to 45 minutes.
