In honor of the day the Pilgrims landed on Plymouth Rock, here’s a rock-shaped cookie stuffed with cranberries, walnuts, and white chips. The fun part is cramming the "rocks" with add-ins, so consider my combination a suggestion and use your favorite nuts, dried fruit, and chips.
Baker’s Notes: The method of folding egg whites into cookie dough is one you don’t see very often these days, but it gives the cookies an interesting sturdy-yet-somehow-light (despite the name) texture.
Preheat the oven to 375 degrees and place a rack in the center. Line 2 baking sheets with parchment paper or nonstick foil.
In the bowl of a stand mixer fitted with a whisk attachment or in a large mixing bowl, using a handheld electric mixer, beat the egg whites on high speed until stiff peaks form. Transfer the whipped whites to a separate bowl to wait. Add the butter, sugar, salt, and vanilla to the mixing bowl and beat on medium-high until creamy. Beat in the egg yolks, scraping the sides of the bowl once or twice. Mix the baking soda and water together to dissolve the baking soda, then add to the batter. Fold in the whipped egg whites, then stir in the flour. The dough will be thick. Stir in the walnuts, cranberries, and white chips.
Drop rounded tablespoonfuls of dough into large rounds about 1½ inches in diameter, about 2½ inches apart, on the prepared baking sheets. Bake 1 sheet at a time for 10 minutes, or until the edges are browned and the cookies appear set. Transfer to a wire rack and let cool completely.