Blow up balloons until they are between 5 and 8 inches in diameter. Spray with cooking spray. Line baking sheet with parchment paper.
Place chocolate chips in microwave-safe bowl, warming 30 seconds at a time and stirring in between each interval. When chocolate is smooth, stop heating.
Allow the chocolate to cool for about 5 minutes, until no longer hot to the touch.
Hold a balloon by the knot and dip into bowl of melted chocolate. For deeper bowls, submerge more of the balloon. Tilt to spread excess chocolate and let drippings run off.
Place a spoonful of melted chocolate onto parchment paper to form base for the bowl. Set chocolate-dipped balloon directly onto spoonful. Repeat for remaining balloons.
Rest in a cool, dry place for 30 minutes.
Gently peel chocolate bowl from parchment paper and pop balloon gently. Remove balloon from the bowl.
To make the mousse, combine heavy whipping cream and jam in bowl. Using stand mixer or hand mixer, whip until stiff peaks form.
Fill each bowl with strawberry mousse, and top with strawberries.