Prepare an 8- or 9-inch square pan lined with parchment paper to prevent sticking.

Blend fresh strawberries and unsweetened applesauce until completely smooth, about 2-3 minutes.

Transfer the puree to a large heat-proof bowl and sprinkle the gelatin powder over it. Stir until combined.

Set up a double boiler and heat the mixture gently for about 5 minutes, stirring continuously until gelatin is dissolved.

Once cooled, transfer the mixture to a stand mixer and beat on high for about 15 minutes until fluffy.

Pour the fluffy strawberry mixture into the prepared pan and smooth the top.

Chill the pan in the refrigerator for at least 1 hour until firm but still airy.

Lift the cake out using the parchment paper, slice, and serve chilled, optionally topped with whipped cream.