We found some variation in how much the cookies spread. So don't be surprised if a single batch features some thin and large with others taller and rounder. Expect a relatively soft and chewy cookie either way.
Make Ahead: The cookies can be stored in an airtight container at room temperature for several days. Cookie dough portions can be frozen for up to 3 months; defrost overnight in the refrigerator or bake directly from frozen, adding baking time as needed
8 tablespoons (1 stick) salted butter, at room temperature
1 1/2 cups sugar
1/2 cup sour cream
1/2 cup heavy whipping cream
1 tablespoon finely grated zest and 3 tablespoons juice from 1 large orange
2 1/2 cups flour
1 teaspoon baking soda
1 teaspoon baking powder
1 cup white chocolate chips
Position racks in the upper and lower parts of the oven; preheat to 350 degrees.
Line three baking sheets with parchment paper. (If you have one or two baking sheets, bake in batches and allow each pan to cool for at least 10 minutes before the next use; also, line with fresh parchment paper.)
Combine the butter, sugar, sour cream, heavy whipping cream and orange juice in the bowl of a stand mixer or use a handheld electric mixer; beat on medium speed for about 2 minutes, until creamy and free of lumps.
Add the orange zest and beat on low speed, just until evenly distributed. Stop to scrape down the bowl.
Add the flour, baking soda and baking powder; begin mixing on low speed and then increase to medium speed and beat just until incorporated, to form a soft, relatively sticky dough.
Reduce the speed to low; add the white chocolate chips and beat until incorporated.
Use two large tableware spoons to drop mounds of about 1 1/2 tablespoons' worth of dough on the baking sheets, spacing the mounds at least 5cm apart. (The spacing is important, as these cookies tend to spread.)
Bake (upper and lower racks for multiple baking sheets; reposition for middle rack when baking one sheet at a time) for 10 to 11 minutes, or until the cookies are golden brown around the bottom edges, rotating the baking sheets from top to bottom and front to back halfway through.
Let cool on the baking sheet for 5 minutes, then transfer the cookies to a wire rack to cool completely before serving or storing.