Creating the Mexican Strawberry Meringue Cake is straightforward when you follow these steps:

1. Preheat the Oven: Preheat your oven to 225°F (110°C). Line two baking sheets with parchment paper.

2. Prepare Meringue Mixture: In a clean mixing bowl, beat the egg whites on medium speed until foamy. Add the cream of tartar and continue beating until soft peaks form.

3. Add Sugar Gradually: Slowly add the granulated sugar, one tablespoon at a time, while beating on high speed until stiff peaks form and the mixture is glossy.

4. Incorporate Cornstarch and Vanilla: Gently fold in the cornstarch and vanilla extract until just combined.

5. Shape the Meringue Layers: Divide the meringue into three equal portions. Spoon each portion onto the prepared baking sheets, shaping them into circles about 8 inches in diameter. Smooth the tops with a spatula.

6. Bake Meringue Layers: Place the baking sheets in the preheated oven and bake for 1 hour. Turn off the oven and let the meringues cool inside for at least 1 hour.

7. Prepare Strawberry Filling: While the meringues cool, combine the sliced strawberries, granulated sugar, and lemon juice in a bowl. Toss gently and let sit for about 30 minutes to macerate.

8. Make the Whipped Cream: In a mixing bowl, whip the heavy cream with powdered sugar and vanilla extract until soft peaks form.

9. Assemble the Cake: Once the meringue layers are completely cool, place one layer on a serving platter. Spread a layer of whipped cream over it, followed by a generous layer of the macerated strawberries.

10. Repeat Layers: Add the second meringue layer and repeat the process of adding whipped cream and strawberries. Top with the final meringue layer.

11. Finish the Cake: Spread the remaining whipped cream on top of the final meringue layer and garnish with additional strawberries.