Lightly spoon flour into a dry measuring cup; level with a knife. Combine flour, cocoa, baking soda, and salt in a large bowl; stir with a whisk. Set aside.
Combine fat-free milk, instant coffee, and vanilla in a medium bowl. Add sugar and eggs, stirring with a whisk until well combined. In a small microwave-safe bowl, melt butter and chocolate chips at high in 20-second intervals, stirring between each interval, until completely melted. Add chocolate mixture to egg mixture, stirring with a whisk until well combined.
Fold egg mixture into flour mixture, stirring just until moist. Spread batter into an 8-inch square baking pan coated with cooking spray. Bake at 350° for 20 minutes or until a wooden pick inserted in center comes out clean. Cool on a wire rack. Cut into 12 pieces.
Place ice cream in a large bowl. Add 4 coarsely chopped candy canes to ice cream, stirring with a wooden spoon until well combined. Return to freezer until ready to serve.
Place 1 brownie on a plate; sprinkle with about 1/8 teaspoon powdered sugar. Top with 1/3 cup ice cream. Garnish with additional candy cane pieces, if desired.