Prepare a water bath in a wide pot, with a thick ring of crumpled tinfoil set inside to later prevent the bowl from touching the bottom of the pot or the water itself. Place over high heat until bubbling-hot, then adjust to maintain a gentle simmer.

Combine egg white, sugar, salt, and lemon juice in the bowl of a stand mixer. Place over the water bath (the bowl should not touch the water). Cook, stirring and scraping continuously with a flexible spatula, until egg whites reach 165°F (74°C). This should take about 6 minutes in a metal bowl.

When the mixture reaches 165°F (74°C), transfer to a stand mixer fitted with a whisk attachment and whip at high speed until the meringue is glossy, stiff, and thick, 3 to 5 minutes.

Once meringue is thick and stiff, whip cream to stiff peaks as well. Add milk to meringue and whisk to combine. Add whipped cream and continue whisking until smooth.

Transfer 7 ounces (198g) of the mixture to a second bowl. To this second bowl, add the freeze-dried strawberry powder and rose water and whisk until homogeneous and thick before transferring to a disposable pastry bag. Add vanilla to the unflavored mixture, whisk to combine, and transfer to another disposable pastry bag.

Place the popsicle molds on a scale. For large (½-cup) bars, fill each mold with about 1 ounce (28g) vanilla cream. For medium (⅓-cup) bars, fill each with about ¾ ounce (21g).

For large (½-cup) bars, pipe about 1 ounce (28g) strawberry cream into the center of each vanilla cream–filled mold. For medium (⅓-cup) bars, pipe about ¾ ounce (21g) strawberry cream into the center of each mold.

Level molds with an offset spatula so that the filling is flush with the top edge of the molds. Cover tightly with foil, then poke a popsicle stick into the center of each mold. Freeze the bars until rock-solid, about 12 hours.

Unmold the ice cream bars by rinsing or standing the molds in hot tap water for a few seconds. Gently wiggle the sticks until the popsicles slide free.

Melt white chocolate over a water bath or in a microwave-safe bowl. Add coconut oil and stir until fully melted and smooth. Cool to about 80°F (27°C).

In the bowl of a food processor, grind freeze-dried strawberries into a fine powder. Add rice cereal to the bowl and pulse until roughly chopped and well coated in powdered strawberries.

Set up a dipping station with the tray of ice cream bars, the jar of white chocolate coating, and the tray of crumbs. Dip each bar into the white chocolate until fully or mostly coated. Transfer to the tray of strawberry/cereal crumbs and press to coat.

Freeze bars until white chocolate has hardened, then transfer to an airtight container and freeze up to 1 month.