Measure all ingredients accurately on a scale. Accuracy ensures correct layering.
Whisk flour, baking powder, and 3 tbsp sugar in a large bowl.
Cut chilled butter into flour using a pastry cutter or finger tips until a coarse crumb texture forms.
Add two beaten eggs (or flaxseed mixture) and stir until a dough forms.
Chill the dough for at least 30 minutes before rolling.
Roll the dough into a rectangle, and fold it like a letter (lamination technique). Repeat the process 3-4 times to create flaky layers.
Roll the dough into a rectangle, and cut into triangle shapes.
In a separate bowl, mix 1 1/2 cups heavy cream, 1 1/2 cups sugar, and 1 tsp vanilla extract. Cook over medium heat until thickened. Cool completely.
Fill each pastry triangle with custard and place fresh strawberries at the base.
Bake the pastries at 375°F (190°C) for 20 minutes or until golden brown.
Prepare the glaze: Whisk 1/2 cup powdered sugar with 1-2 tbsp milk or juice until smooth. Drizzle over cooled pastries.