In a chilled mixing bowl, combine the cold whipping cream and white sugar. Using an electric hand mixer fitted with a whisk attachment, whip the cream until it reaches a thick yogurt-like consistency.

Add the strawberry jam to the whipped cream. Using an electric hand mixer, whip it lightly or use a spatula to fold the jam in gently, using a cutting motion through the center and turning the bowl as you go.

Pour in the whole milk and fold again until everything comes together into a smooth, cohesive strawberry cream mixture.

Transfer the mixture to a piping bag for the cleanest, mess-free filling. Snip off the tip and pipe the strawberry cream into your popsicle molds, filling each cavity almost to the top. If you don't have a piping bag, a spoon or small pitcher works just fine—just work carefully.

Once all molds are filled, gently tap each mold against the counter two or three times. This helps any trapped air bubbles rise to the surface, ensuring your popsicles have a smooth, even texture without unsightly holes or pockets.

Secure the lids tightly on your popsicle molds. Place the molds in the freezer on a flat surface and freeze for at least 4 hours, though overnight is even better. The popsicles need to be completely solid before unmolding—rushing this step can lead to breakage or a mushy texture.

When you're ready to serve, remove the molds from the freezer. If your popsicle molds are stubborn, run the outside of the mold under warm running water for 10-15 seconds to gently loosen the popsicles. Pull them out carefully and enjoy immediately.