Heat the oven to 350°F and spray two 8x8-inch cake pans with non-stick cooking spray.
In the work bowl of a stand mixer fitted with the paddle attachment, or in a medium bowl with a hand mixer, combine the brown sugar, sugar and butter. Cream together until just combined but not fluffy, about 30 seconds. Add the egg and vanilla and beat on medium speed until lighter in color, about 1 minute.
Add the flour, baking soda, salt and baking powder and mix on low speed to just combine then add the buttermilk and mix on medium-low speed until the batter has no large lumps.
Remove 1/2 of the batter and set aside. To the remaining batter, add the LUCKY LEAF Premium Peach Pie Filling. Mix on low speed until combined, about 30 seconds. Spread the batter into one of the prepared pans. Now, add the reserved batter back to the bowl with the LUCKY LEAF Premium Blueberry Pie Filling. Mix on low speed until well combined, about 45 seconds. Spread the batter into the remaining pan.
Bake for 16 to 20 minutes, or until the cakes pull away from the sides of the pans and the center of the cakes spring back when gently pressed. Cool for 10 minutes in the pan then turn out onto a wire rack to cool to room temperature.
While the cakes cool, prepare the mousse fillings.
In three small bowls divide the gelatin and water. Mix to combine and let stand at room temperature for 10 minutes to bloom.
Heat one of the bowls of gelatin in the microwave for 8 seconds to melt. Set aside to cool slightly. In the work bowl of a stand mixer fitted with the whip attachment, or a large bowl with a hand mixer, combine 1/3 of the cream, 2 Tablespoons of powdered sugar and 1 teaspooon of vanilla. Mix on medium speed until the mixture starts to thicken, about 40 seconds, then pour in the melted gelatin and increase the speed to high until the cream forms soft peaks, about 35 to 40 seconds.
Puree the LUCKY LEAF Premium Peach Pie Filling and add to the gelatin mixture. Continue to whip until the mixture forms firm peaks, about 30 to 45 more seconds. Transfer the mixture to a clean bowl, cover with plastic and chill for 1 hour.
Repeat the puree process with the LUCKY LEAF Premium Blueberry Pie Filling. With the remaining cream, prepare it like the step above, omitting the peach filling and whip to medium firm peaks.
To assemble, cut each cake into 1/2-inch cubes. In one large trifle dish, or in eight individual dishes, place an even layer of blueberry cake, then spread over all the peach mousse, then the peach cake cubes, then all of the blueberry mousse. Finally top the trifle with the plain whipped cream. Chill for at least 1 hour before serving.