1 cup
all-purpose flour, spooned into measuring cup and leveled-off
1 cup
granulated sugar
½ cup
unsweetened natural cocoa powder (such as Hershey’s)
½ teaspoon
salt
1 teaspoon
baking powder
½ teaspoon
baking soda
1 large
egg
¼ cup
vegetable oil
½ cup
sour cream
¾ teaspoon
vanilla extract
½ cup
boiling water
1
(3.9 oz) box instant chocolate pudding
1
(14 oz) can sweetened condensed milk
1 cup
cold water
4 cups
heavy cream
2 tablespoons
confectioners' sugar
1
(11.7 oz) package mint Oreo Thins or similar chocolate mint sandwich cookies, broken or chopped into ½-inch pieces (reserve 6 whole cookies for decorating the top)