Ingredients
• ¾ cup unsalted butter (melted, not margarine)
• ¾ cup light brown sugar, packed
• ½ cup granulated sugar
• 1 large egg + 1 egg yolk
• 2 teaspoons vanilla extract
• 1 teaspoon baking soda
• ¼ teaspoon baking powder
• ½ teaspoon salt
• 2 cups all-purpose flour (add an extra ¼ cup if dough is too runny)
• 1½ cups semi-sweet chocolate chips
• ½ cup whole chips (for inside the dough)
• ½ cup chopped chips (for inside the dough)
• ½ cup whole chips (for sprinkling on top)
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Instructions
1. Preheat oven to 350°F (175°C). Grease or line a 9×13-inch baking pan with parchment paper, leaving some overhang for easy removal.
2. Prep chocolate chips
• Place ½ cup of chocolate chips on a cutting board.
• Chop them into small pieces with a sharp knife.
• Set aside (these help give chocolate speckles throughout the bars).
3. Melt the butter
• In a microwave-safe bowl, melt ¾ cup unsalted butter until fully liquid.
• Let it cool slightly so it’s warm but not hot (so you don’t cook the eggs).
4. Mix wet ingredients
• In a large mixing bowl, whisk together melted butter, light brown sugar, and granulated sugar until smooth.
• Add 1 egg + 1 egg yolk and vanilla extract. Whisk until fully combined.
5. Add dry ingredients
• Sprinkle in baking soda, baking powder, salt, and flour.
• Mix gently with a spatula until just combined — do not overmix.
6. Add chocolate chips
• Fold in ½ cup whole chocolate chips and ½ cup chopped chocolate chips into the dough.
7. Transfer to pan
• Spread the dough evenly into your prepared pan.
• Sprinkle the remaining ½ cup whole chocolate chips on top, pressing them lightly into the dough.
8. Bake
• Bake for 22–28 minutes, or until the edges are golden brown and the center looks set but still slightly soft.
• A toothpick inserted in the center should come out with moist crumbs, not raw batter.
9. Cool & serve
• Allow the bars to cool in the pan for at least 20 minutes before slicing into squares or rectangles.
• Enjoy warm for a gooey texture or let cool completely for firmer bars.
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Notes & Tips
• Why extra yolk? The yolk adds richness and chewiness without making the bars cakey.
• Avoid overbaking — these continue to cook as they cool.
• Make ahead: Store in an airtight container at room temperature for up to 4 days or freeze for up to 2 months.
• Variation idea: Add chopped nuts, white chocolate, or even caramel bits for extra flavor.