Ingredients
Equipment
Method
- Position the oven rack in the middle position and heat the oven to 350°F (175°C), then line a 9×13 inch light-colored aluminum pan with parchment paper leaving 2 inches of overhang on both long sides.
- Melt the butter in a large mixing bowl, then set aside for 8–10 minutes until neutral to the touch — not warm, not cool.
- Add the packed light brown sugar and granulated white sugar to the cooled melted butter and whisk in wide circular strokes for approximately 30 strokes until the mixture looks smooth, glossy, and uniform with no visible dry sugar pockets.
- Add the eggs and egg yolk one at a time, whisking each in completely before adding the next, then whisk in the pure vanilla extract until fully incorporated.
- Add the unfed sourdough discard at room temperature and fold with a silicone spatula in slow bottom-upward strokes for approximately 15 strokes until no white streaks remain and the batter looks smooth and unified.
- Add the all-purpose flour, baking soda, and fine sea salt to the bowl and fold with the silicone spatula using bottom-upward strokes — 25 strokes maximum from the moment the flour touches the batter — until just incorporated with no dry streaks remaining.
- Add 2 cups (340g) of the semi-sweet chocolate chips and fold in with approximately 10 bottom-upward strokes until evenly distributed, then transfer the dough to the prepared pan and press into an even layer using the spatula and damp fingertips.
- Scatter the reserved ¼ cup (43g) chocolate chips evenly across the top surface and press in gently, then place the pan on the middle rack of the preheated oven.
- Bake at 350°F (175°C) for 25–28 minutes until the surface looks matte and set across the full slab and the edges are golden-brown, checking at 22 minutes — the center should still have a faint give when the pan is gently shaken at pull time.
- Remove the pan from the oven and immediately scatter the flaked sea salt evenly across the entire top surface within 30 seconds of pulling.
- Place the pan on a wire cooling rack and leave completely undisturbed for a minimum of 2 hours before cutting, then use the parchment overhang to lift the full slab onto a cutting board and cut into 24 bars with a sharp knife wiped clean between cuts.
Notes
- Flour: spoon and level — never scoop directly from the bag. Excess flour produces dry, cakey bars. Use a scale if possible.
- Sourdough discard: use unfed discard 1–14 days old, stored in the fridge, brought to room temperature before use.
- Butter: must be melted and cooled to neutral — warm butter above 85°F (29°C) will scramble the eggs on contact.
- Eggs: must be at room temperature — cold eggs cause the melted butter to solidify in uneven clumps.
- Baking soda: drop ½ tsp into 2 tbsp hot water — if it does not bubble vigorously, replace it.
- Sea salt finish: use flaked sea salt only — fine salt dissolves and disappears. Add within 30 seconds of pulling from the oven.
- Pan: light-colored aluminum only — dark pans overbake the edges before the center sets.
- Storage: lidded hard-sided container, parchment between layers, room temperature up to 5 days. Best on day 2–3.
- Freeze baked: wrap individually in plastic wrap, freeze up to 2 months, thaw at room temperature 45–60 minutes.
- Freeze unbaked: press into lined pan, wrap tightly, freeze up to 1 month — bake from frozen at 350°F for 32–38 minutes.
- Make ahead: bake up to 5 days ahead — flavor and chew improve by day 2.
- Scaling: do not double the baking soda — increase by 50% only for a doubled batch. Bake in two separate 9×13 pans.
- Altitude: above 3,500ft reduce baking soda by ⅛ tsp and increase oven to 360°F (182°C).
- Allergens: contains gluten, dairy, eggs, and soy (check chocolate chip packaging). For dairy-free, substitute plant-based butter at equal weight.
- Tip: run the knife under hot water and dry before each cut for clean edges through the chocolate pockets.