Once the cake has completely cooled to room temperature, carefully slice the cake twice horizontally to get 3 even layers
Place a fine mesh sieve over a bowl. Pour the peaches into the fine mesh sieve to remove the liquid from them.
Place the bottom half of the cake back into the springform pan, and brush half of the peach liquid over the cake.
Spread 1/3 of the mascarpone whip onto the bottom cake layer, followed by 1/2 of the peaches.
Place the middle cake layer on top, then brush the remaining peach juice over it.
Spread 1/2 of the remaining mascarpone whipped cream on to the cake, followed by the remaining peaches.
Place the top cake layer on top, pushing it down slightly to secure it.
Cover the cake with plastic wrap and leave it in the fridge to set for at least 10 minutes.
Once you're ready to serve the cake, spread the remaining mascarpone whipped cream on top. If desired, garnish with an additional sliced peach (no brown sugar/lemon juice required!) Slice, serve, and enjoy!