Make the Strawberry Reduction Sauce. Puree 225 g fresh or frozen strawberries. Transfer into a saucepan, add sugar and lemon juice. Simmer the strawberry sauce until thickened and reduced to 2/3 cup. Set aside and let it cool. You can make this ahead the. Refrigerate until ready to use.
Preheat the oven to 350°F and prepare the 12-cup muffin pan with paper cupcake liners.
Make the strawberry cake batter. In a medium-sized mixing bowl, beat together the eggs, lemon juice, and sugar for 5 minutes on high speed or until light and pale in color. Add the oil and strawberry reduction sauce. Sift together all-purpose flour, cornflour, baking powder, and salt over the egg mixture. Mix until combined then add the heavy cream or full-fat milk. Mix until blended.
Divide the cake batter evenly using a large ice cream scoop or 1/4 cup measuring cup. Fill each cup about 2/3 cup full. Add red icing coloring or chopped strawberries, if desired.
Bake in preheated oven at 350°F for about 15 to 20 minutes. Depending on your oven, or until the inserted toothpick into the middle of a cupcake comes out clean.
Cooling the cupcakes. Remove from the oven and let it cool in the muffin pan for 10 minutes then transfer on a cooling wire rack to cool completely. Spread or brush the top of the cupcakes with strawberry jam, if desired.
Make the strawberry whipped cream cream cheese frosting. In a bowl of a stand mixer with a whisk attachment, beat cold cream cheese and sugar. Scrape the bottom of the bowl then gradually add cold heavy cream. Then add the strawberry reduction sauce and red icing color. Beat until light and fluffy. Transfer into a piping bag with a decorative tip.
Decorate the strawberry cupcakes. Frost each cupcake and garnish with strawberries.