Refrigerating the dough has everything to do with it. With room temperature dough, the butter begins to melt quicker and the cookies will spread in the oven before they begin to set up making for a flatter, crisper cookie.
I have the ATK cookbook and they have 3 variations on the perfect chocolate chip cookie. The classic, the thick and chewy and the thin and crispy. The one that calls for 3/4 brown sugar is the classic recipe. Here is the recipe for the thin and crispy:
1 1/2 cups of unbleached all-purpose flour
3/4 teaspoon of baking powder
1/4 teaspoon of salt
8 tablespoons (1 stick) unsalted butter, melted and cooled
1/2 cup of granulated sugar
1/3 cup packed light brown sugar
2 tablespoon light corn syrup
1 large egg yolk
2 tablespoons of milk
1 tablespoon vanilla extract
3/4 cup semi-sweet chocolate chips
Adjust oven rack to the medium position and preheat oven to 375°F. Line 2 large baking sheets with parchment paper.
Whisk the flour, baking powder and salt together in a medium bowl; set aside.
In a standing mixer fitted with a paddle attachment, beat the melted butter, sugar, brown sugar and corn syrup at low speed until thoroughly blended, about 1 minute. Add the egg yolk, milk and vanilla; mix until incorporated and smooth, about 1 minute, scrapping down the bowl and beater when needed. With the mixer still running on low, slowly add the dry mixture and mix until just combined. Do not over beat. Add the chocolate chips and mix until evenly distributed throughout batter, about 5 seconds.
Divide the dough into 40 portions, about 1 tablespoon and roll them between your hands into balls. Place the cookies on the prepared baking sheet, spacing them about 2 inches apart. Bake, one sheet at a time until the cookies are deep golden brown and flat, about 12 minutes switching and rotating the baking sheets halfway through the baking time.
Cool the cookies on the baking sheet 3 minutes. Using a wide metal spatula, transfer the cookies to a wire rack and cool to room temperature.
Again, refrigerating the dough WILL make a difference no matter which recipe you use so don't refrigerate it.
Oh....and welcome to the forum
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