Chocolate-Toffee Bark

Make foil sling for 13 by 9-inch baking pan by folding 2 long sheets of aluminum foil; first sheet should be 13 inches wide and second sheet should be 9 inches wide. Lay sheets of foil in pan perpendicular to each other, with extra foil hanging over edges of pan. Push foil into corners and up sides of pan, smoothing foil flush to pan. Spray foil with vegetable oil spray.

Heat butter and water in medium saucepan over medium-high heat until butter is melted. Add sugar, corn syrup, and salt to saucepan. Bring mixture to boil and cook, without stirring, until sugar is completely dissolved and syrup is faint golden color, 10 to 14 minutes.

Reduce heat to medium-low and continue to cook, gently swirling saucepan, until toffee is amber-colored and registers 350 to 360 degrees, 2 to 4 minutes longer. Off heat, stir in ½ cup pecans until incorporated and thoroughly coated.

Pour toffee into prepared pan and smooth into even layer with spatula. Cool to room temperature, about 30 minutes.

Microwave 3 ounces chocolate in bowl at 50 percent power, stirring frequently, until about two-thirds melted, 1 to 2 minutes. Remove bowl from microwave, add 1 ounce chocolate, and stir until melted, returning to microwave for no more than 5 seconds at a time to complete melting if necessary. Pour chocolate over hardened toffee and smooth with spatula, making sure to cover toffee layer evenly and completely. Sprinkle with ½ cup pecans and press lightly to adhere. Refrigerate, uncovered, until chocolate has hardened, about 15 minutes.

Line rimmed baking sheet with parchment paper. Using foil sling, invert toffee onto prepared sheet. Discard foil.

Microwave 3 ounces chocolate in bowl at 50 percent power, stirring frequently, until about two-thirds melted, 1 to 2 minutes. Remove bowl from microwave, add remaining 1 ounce chocolate, and stir until melted, returning to microwave for no more than 5 seconds at a time to complete melting if necessary. Pour chocolate over hardened toffee and smooth with spatula, making sure to cover toffee layer evenly and completely. Sprinkle with ½ cup pecans and press lightly to adhere. Refrigerate, uncovered, until chocolate has hardened, about 15 minutes.

Break bark into rough squares and serve. (Bark can be stored at room temperature for up to 2 weeks.)