Ingredients
Equipment
Method
- Position oven rack in the middle position and preheat to 350°F (175°C). Line a 9×13 inch (23×33cm) light-colored aluminum baking pan with parchment paper, pressing it flat against the bottom and up both long sides with at least 2 inches of overhang on each side.
- In a large mixing bowl, whisk together 1 cup (227g) melted cooled unsalted butter and 2 cups (440g) packed dark brown sugar until fully combined and no dry sugar streaks remain — approximately 30 to 40 strokes. The mixture should look thick, glossy, and uniform.
- Add 2 large room-temperature eggs one at a time, folding with a silicone spatula after each addition until fully incorporated before adding the next. Add 2 teaspoons (10ml) pure vanilla extract and fold until combined.
- In a separate bowl, whisk together 2¼ cups (270g) all-purpose flour spooned and leveled, 1 teaspoon (4g) baking powder, and 1 teaspoon (6g) fine sea salt. Add the dry ingredients to the wet ingredients and fold with a silicone spatula using slow bottom-to-top strokes — 20 strokes maximum. Stop the moment no dry flour streaks remain.
- Add 1½ cups (255g) semi-sweet chocolate chips, 1 cup (170g) Heath toffee bits, and 1½ cups (120g) sweetened shredded coconut. Fold with 15 to 20 strokes until evenly distributed. Do not overmix.
- Transfer batter to the prepared pan and spread into an even layer using the back of the spatula, pressing firmly into the corners. Scatter ½ cup (40g) topping coconut evenly across the surface and press lightly with your palm. Scatter ¼ cup (43g) reserved chocolate chips across the top and press each chip lightly to half-embed.
- Bake at 350°F (175°C) on the middle rack for 28 to 32 minutes, until the edges are deep amber-brown and pulled from the pan sides and the surface coconut is golden-toasted. The center will look slightly underdone — this is correct.
- Remove from the oven and place on a wire rack. Cool in the pan for a minimum of 2 hours before cutting. For cleanest cuts, refrigerate for 30 minutes after the room-temperature rest, then lift the slab from the pan using the parchment overhang, place on a cutting board, and cut into 24 bars using a sharp knife wiped clean between each cut.
Notes
Use packed dark brown sugar — light brown sugar will not produce the amber toffee layer visible in the cross-section.
Butter must be cooled to barely warm before adding eggs — hot butter scrambles the eggs and breaks the batter.
Use Heath toffee bits from the baking aisle, plain variety only — not chocolate-covered, not caramel bits.
Sweetened shredded coconut is required in the batter for correct moisture and chew — unsweetened produces drier bars.
Do not cut before 2 hours — the toffee center is still liquid and will collapse if the knife goes through too early.
Light-colored aluminum pan only — dark pans overbrown the bottom. Reduce temp to 325°F (165°C) if using dark pan.
High altitude above 3,500 feet: reduce baking powder to ¾ tsp (3g) and start checking at 25 minutes.
Allergens: contains gluten (wheat), dairy (butter), eggs, and tree nuts (coconut). Heath toffee bits contain dairy.
Make ahead: bars improve on Day 2. Store in a lidded hard-sided container with parchment between layers, room temperature up to 4 days.
Freeze baked bars individually wrapped in plastic wrap up to 2 months. Thaw on a wire rack at room temperature 45 to 60 minutes.
Scale to 8×8 pan: halve all ingredients, use ½ tsp baking powder, bake 34 to 38 minutes.