Lightly spray an 8x8-in. baking pan with nonstick spray. Line baking pan with waxed paper, pressing paper into pan to adhere and extending the paper over edges of pan. Set pan aside.

Whisk together oat flour, powdered peanut butter, cocoa, protein powder and beet powder in a medium bowl. Stir in almond milk and vanilla. Lightly spray hands with nonstick spray; knead mixture in bowl for 3 to 5 minutes or until well combined and mixture forms a ball.

Transfer mixture to prepared baking pan. Place an additional sheet of waxed paper on top of mixture; firmly press mixture evenly in pan. Discard top sheet of waxed paper.

Microwave white chocolate chips and shortening in a small microwave-safe bowl on HIGH at 15-second intervals or until melted, stirring each time.

Use waxed paper to lift bar mixture out of pan; place on a cutting board. Set aside 1 Tbsp. melted chocolate for drizzling. Spread remaining white chocolate mixture evenly on top. Freeze for 2 to 3 minutes or until chocolate is set.

Turn bar mixture over on cutting board; remove waxed paper. Cut into 10 bars. Drizzle half of each bar with reserved 1 Tbsp. white chocolate mixture. Return bars to freezer for 3 to 5 minutes or until chocolate is set. Store covered in refrigerator up to 5 days.