Orange Chocolate Chip Cookies
["1 orange", "3/4 tsp. baking soda", "6 oz. unsalted butter (at room temperature)", "1/2 c. granulated sugar", "1 egg", "1/2 tsp. vanilla extract", "12 oz. semi-sweet chocolate chips (2 c.)", "1 3/4 c. flour", "1/2 tsp. salt", "1/4 c. brown sugar", "1 egg yolk"]
["Grate 1 1/2 teaspoons of the colored zest from the orange and squeeze 2 tablespoons juice.", "Combine the flour, soda and salt. Beat butter, sugars and orange zest until fluffy.", "Beat in egg yolk, vanilla and orange juice.", "Beat in flour mixture.", "Stir in chocolate chips with a spoon.", "Drop by teaspoonfuls, about 2-inches apart onto ungreased baking sheets.", "Bake until edges start to brown.", "Let stand on baking sheets for 1 minute and remove to wire racks."]
["orange", "baking soda", "unsalted butter", "sugar", "egg", "vanilla extract", "semi-sweet chocolate chips", "flour", "salt", "brown sugar", "egg yolk"]