Preheat oven to 350 degrees F (175 degrees C). Line a baking sheet with parchment paper.
Sift the self-rising flour, 1/3 cup of sugar, and cinnamon in a large mixing bowl. Mix in the cold butter pieces, and chop the butter into the flour mixture with a pastry cutter until the mixture looks like crumbs. In a separate bowl, whisk the egg and whipped cream together, and pour into the bowl containing the flour mixture; add milk and vanilla extract. Stir to make a dough.
Turn the dough out onto a floured surface and knead until smooth, about 1 minute. Spread the dough onto the prepared baking sheet. Sprinkle with 2 tablespoons of sugar.
Bake in the preheated oven until golden brown, about 20 minutes; allow the cake to cool completely. With a heart-shaped cookie cutter, cut out 16 hearts from the cake. It helps to wiggle the cutter slightly while cutting. Remove cut-outs carefully to avoid breaking.
Mix strawberries with 3 tablespoons of sugar in a bowl; place a shortcake heart on a plate, and top with sweetened strawberries, then spoon about 2 tablespoons of whipped cream on the berries. Top with another heart-shaped shortcake and serve.