Line an 8×8-inch square tin with parchment, allowing a 1-inch overhang on all sides. Spray generously with nonstick spray.

Pour 120 milliliters (1/2 cup) water into a large mixing bowl (if using a hand mixer), or the bowl of a stand mixer. Sprinkle gelatin evenly over the water. Set aside.

In a large, heavy-bottomed stock pot, combine granulated sugar, corn syrup, remaining water, and fine sea salt. Bring to a boil and boil, without stirring, until syrup reaches 240° F (116° C) on a candy thermometer.

Carefully pour hot syrup over gelatin. Mix on high speed for 2-3 minutes, or until mixture begins to thicken. Add strawberry flavoring and pink food coloring and continue mixing on high speed until very thick and voluminous, about 8-9 minutes more. Add crushed freeze-dried strawberries and mix on low for 15-30 seconds, or until just incorporated into the marshmallow fluff.

With an oiled rubber spatula, scrape marshmallow mixture into prepared tin.

Loosely cover with a well-oiled sheet of aluminum foil. Allow to set at room temperature until firm, at least 4 hours, or overnight.

Cutting and Coating:

In a small bowl, whisk potato starch and icing sugar.

Generously dust a large chopping board with the starch-sugar mixture. Lifting by the parchment, transfer marshmallow slab onto dusted work surface. Coat top of slab with more of the powder.

With a well-oiled metal cutter, cut the marshmallow slab into hearts.***

Toss cut marshmallows in additional powder, coating all sides evenly.

Store strawberry marshmallows in an airtight container at room temperature for up to 1 month.