To make the batter: Place the egg whites in a clean, grease-free bowl, and whip them until frothy.
Add the sugar and whip until soft peaks form. Set this mixture aside.
In a medium-sized mixing bowl, whisk together the egg yolks and cream, then add the salt, vanilla, melted butter and flour. Whisk until smooth.
Heat a 10" pan with heatproof handle over medium-low heat (an omelet pan or cast iron skillet works well). Spray the pan with non-stick vegetable oil spray, or rub it with a bit of vegetable oil.
Gently fold the egg whites into the batter.
Pour the batter into the heated pan, and swirl the pan gently.
Continue to cook for about 3 to 5 minutes, until the bottom is light brown.
Place the pan in the oven and bake the "cake" for 10 to 12 minutes, until it's puffy and set.
To make the filling: While the cake is baking, melt the butter in a small skillet.
Add the corn syrup and sugar, then bring to a boil.
Add the strawberries, lemon juice and cinnamon. Stir to coat the strawberries with the sauce, then remove from the heat.
Remove the cake from the oven, and slip it onto a serving platter.
Spread the strawberries over half of the cake, then fold it over to cover the filling (as you'd fold an omelet). Dust the edges with confectioners' sugar, and garnish with a dollop of sour cream or crème fraîche and serve immediately.