Prepare the Meringue: In a planetary mixer or with an electric mixer, whip the egg whites at room temperature with half of the sugar and lemon juice until starting to form peaks. Then add the remaining sugar and continue whipping until stiff peaks form.
Pipe and Bake Meringue Discs: Transfer the meringue into a piping bag fitted with a smooth nozzle. On two baking trays lined with baking paper, draw two 20 cm diameter circles. Pipe two discs and use leftover meringue to make small decorative meringues. Bake in a static oven preheated to 90°C for approximately 4 hours.
Prepare the Custard: In a saucepan, pour milk and add lemon zest (yellow part only). Bring to a boil. Meanwhile, mix sugar and egg yolks in a bowl without whipping. Combine corn starch and rice starch. When milk is near boiling, pour it gradually into the egg mixture through a sieve to retain lemon zest. Stir well and return to the pan. Cook over medium heat, stirring constantly until the custard almost boils and thickens. Pour into a dish, cover with cling film, and cool first at room temperature then refrigerate.
Whip the Cream: Lightly sweeten the cold fresh cream with powdered sugar and whip until soft peaks form. Transfer to a piping bag with a smooth nozzle.
Assemble the Meringue Cake: Place the first meringue disc on a serving plate. Pipe a border of whipped cream tufts around the edge. Whisk the chilled custard to loosen it and pipe it into the center. Add cubed fresh strawberries, pressing lightly to level. Place the second meringue disc on top. Pipe another border of whipped cream tufts on top and spread a layer of custard. Decorate with quartered strawberries, small meringues, and fresh mint leaves.
Chill Before Serving: Let the assembled cake rest in the refrigerator for some time before serving to enhance freshness and flavor.