Line an 8-inch or 9-inch square pan with one large sheet of parchment paper. Make sure the sheet covers the bottom and all sides — this makes lifting the set cake out much easier.

Add the chopped strawberries and applesauce to a blender. Blend on high until the mixture is completely smooth and a uniform pink color.

Pour the puree into a large heatproof mixing bowl. Sprinkle the gelatin evenly over the surface. Whisk well until fully incorporated. The mixture should begin to thicken slightly — that’s the gelatin starting to absorb moisture.

Place the bowl over a pot of simmering water (double boiler method). Stir the mixture gently but continuously until the gelatin is fully dissolved. Be careful not to let the mixture boil or get too hot. Once dissolved, the puree will appear smoother and slightly more fluid.

Remove the bowl from the heat and let it sit at room temperature for about 10 minutes to cool.

Transfer the mixture into the bowl of a stand mixer fitted with the whisk attachment. Beat on high speed for about 15 minutes. The mixture will triple or quadruple in volume and take on a fluffy, mousse-like texture. When the whisk is lifted, it should hold soft peaks.

Pour the whipped mixture into your prepared pan. Use a spatula to smooth the surface evenly. Refrigerate for at least 1 hour or until fully set.

Once chilled, lift the cake out of the pan using the parchment paper. Slice with a large, sharp knife. Serve as-is or top with whipped cream, sliced berries, or a dusting of powdered sugar.