Preheat oven to 350°F (180°C). Line 2 baking sheets with parchment paper. Set aside.
Place egg yolks, ¼ cup of the sugar, vanilla, salt, and food colouring in a large mixing bowl. Beat on medium speed until the egg yolks lighten in colour and the mixture increases in volume. Set aside.
Add egg whites to a large mixing bowl. Beat on high speed. Add the remaining ¼ cup sugar, a bit at a time, until soft peaks form. Beat for another 2 minutes until egg whites are glossy.
Fold the egg whites into the egg yolk mixture in batches until combined. Be careful to not deflate the egg whites.
Sift flour, cornstarch, and strawberry powder into the batter and fold in until no dry streaks remain. Careful to not overmix. Batter will be a bit lumpy.
Transfer the batter into a large piping bag with a large round tip. Pipe batter into 4 inch long lines, about 1 inch wide on the prepared baking sheets. Space cookies about 2 inches apart.
Dust the piped cookies with powdered sugar. Bake cookies for 13-15 minutes, or until lightly golden. Continue piping the cookies on the next baking sheet, and dust them with powdered sugar before baking.
Store cookies in an airtight container for up to 1 week.