Remove the leaves from the strawberries, weigh them, and blend into a purée using an immersion blender or food processor. If needed, purée a slightly larger amount and save the extra for another use.
Here’s a handy trick—whisk the cake flour with the oil first. This helps reduce gluten formation and leads to a more tender crumb.
Next, add in the strawberry purée, egg yolks, and a few drops of red gel food coloring. Without food coloring, the cake may turn brownish after baking due to natural strawberry pigments. While the flavor remains the same, a small amount of food coloring will help retain that lovely pink hue.
The finished batter should be thick yet pourable.
Make the Meringue:
Beat the egg whites at medium speed until frothy, then add lemon juice, vinegar, or cream of tartar. Continue to beat until the mixture becomes whitish and bubbles are fine.
Gradually add the sugar in three additions while continuing to beat on medium speed (speed 6 on a KitchenAid). Though it takes longer than high speed, this gentler method results in a smoother, more stable meringue. Scrape down the sides of the bowl occasionally to ensure no sugar is left unmixed.
Continue whipping until stiff peaks form—tips should slightly curl over. Then, lower the speed to 4 and beat for 1 more minute to smooth out any large air bubbles.