For the Cream Crumbs:
(makes around 1 1/2 cups)
1/4 cup plus 2 tablespoons milk powder, divided into 1/4 cup and 2 tablespoon portions
2 tablespoons all-purpose flour
1 tablespoon cornstarch
1 tablespoon granulated sugar
1/4 teaspoon kosher salt
2 tablespoons unsalted butter, melted and cooled
1 1/2 ounces white chocolate, melted and cooled

For the Cookies:
(makes around 20 3-inch cookies)
2 cups all-purpose flour
1/2 teaspoon baking powder
1/4 teaspoon baking soda
1 teaspoon kosher salt
1 cup (2 sticks) unsalted butter, at room temperature
3/4 cup granulated sugar
2/3 cup light brown sugar, tightly packed
2 large eggs
3/4 cup Oreo crumbs (around 12 Oreo cookies — but see baker's note)
1 1/2 cups cream crumbs (1 portion from recipe above)