Line an 8-inch square pan with parchment paper, leaving some overhang on two sides for lifting. Lightly grease the parchment and any exposed pan surface with neutral oil or nonstick spray.

Pour 1/4 cup cold water into the bowl of a stand mixer and sprinkle the gelatin evenly over it. Let it stand for 5–10 minutes so the gelatin fully blooms and hydrates.

Add the remaining 1/4 cup water and the allulose to a small saucepan. Warm over medium heat, stirring until dissolved, then bring the syrup to a simmer and cook until it reaches approximately 240°F (115°C), avoiding prolonged boiling because allulose can brown.

Set the mixer to low and slowly pour the hot allulose syrup into the bloomed gelatin. Increase the speed to high and whip for approximately 8–12 minutes, until the mixture is thick, glossy, and substantially larger in volume.

Beat in the vanilla extract and fine salt, adding the peppermint extract too if you want a mint flavor. Scrape the bowl briefly so the flavorings are evenly distributed without deflating the mixture.

Immediately spread the marshmallow mixture into the prepared pan. Use a lightly oiled spatula to smooth the top because the mixture begins setting as it cools.

Refrigerate the pan or leave it at cool room temperature until firm, usually 2–4 hours. Lift the slab using the parchment overhang and cut it into 24 small pieces with a lightly greased knife.

For cleaner dipping, chill the cut marshmallows for 15–20 minutes before coating. This brief chill helps them hold their shape while the warm chocolate is applied.

Melt the sugar-free chocolate and coconut oil or cocoa butter together in short microwave intervals, stirring between each interval, or melt them gently over a double boiler. Stop heating as soon as the mixture is smooth to prevent scorching.

Dip each marshmallow into the melted chocolate, turning it with a fork or dipping tool until coated. Let excess chocolate drip back into the bowl, then place the marshmallow on parchment.

Refrigerate the coated marshmallows for 10–15 minutes, or until the chocolate shell is set. Store the finished treats in an airtight container in the refrigerator for up to about 1 week, separating layers with parchment.