Spray 6- to 7-inch (1 ½-quart) soufflé dish or round baking dish that fits inside of Crockpot™ Express Pressure Cooker with nonstick cooking spray. Prepare foil sling.* Place rack in Cooking Pot; add water.
To prepare cake, whisk baking mix, granulated sugar and ¼ cup poppy seeds in medium bowl. Blend sour cream, egg, milk, orange peel and vanilla in separate medium bowl. Whisk dry ingredients into sour cream mixture until thoroughly blended.
Spoon batter into prepared dish; smooth top. Cover dish with foil; place in Cooking Pot using foil sling. Secure lid. Press DESSERT, set temperature to HIGH and time to 50 minutes. Make sure Steam Release Valve is in the "Seal" (closed) position. Press START/STOP.
Once cooking is complete, natural release pressure 10 minutes. Release remaining pressure. Remove dish from Cooking Pot using foil sling. To prepare glaze, whisk orange juice into powdered sugar in small bowl. Cut cake into wedges; spread glaze over top and sides of each wedge. Sprinkle wedges evenly with 1 tablespoon poppy seed; let stand until glaze to set.
*Prepare foil sling by tearing off one 18-inch long piece of foil; fold in half lengthwise to create 18X6-inch strip. Place underneath prepared dish. Pull the ends of the strips up and over the dish. Leave the strip in during cooking so you can easily lift the dish out again when cooking is complete.