Whisk together 3 ½ cups of flour, 2 tablespoons sugar, 2 teaspoons salt, and 2 teaspoons instant yeast.
Grate in 3 tablespoons of butter.
Place mixture into the bowl of a stand mixer with a dough hook attachment and start on low speed.
Slowly pour 1 ¼ cups of milk into the dough.
Increase the speed of the mixer and allow to knead the dough for 5-6 minutes, until the dough pulls away from the bowl and is soft.
Turn the dough out onto a floured surface, shape it into a ball and cover and refrigerate for 30 minutes.
Remove from the fridge. Use a rolling pin to roll out the dough to a 9 x 15-inch rectangle, cover and refrigerate for 4 hours, up to overnight.
Beat 1 ½ cups butter and 2 tablespoons flour in a stand mixer using a whisk attachment.
Place the butter onto a piece of parchment paper and cover it with another sheet of parchment paper.
Using a rolling pin, roll out the butter into a 6 x 11 rectangle and chill for 30 minutes.
Remove butter and dough from the fridge. Place the butter in the center of the dough and fold the dough over the edges. Fold the dough ‘hamburger style’ into thirds.
Again, roll out the dough into a 9 x 15-inch rectangle. Fold the dough in thirds. Roll out the dough again into a 9 x 15-inch rectangle, and fold again into thirds.
Chill for 30 minutes and repeat this process two more times.
Chill the dough for 4 hours up to overnight.
Roll out the dough into a 9 x 15-inch rectangle.
Using a sharp knife or pizza cutter, slice the dough in half lengthwise.
Cut each half of the dough into fourths, and then cut each of these in half diagonally.
Stretch each triangle a bit. Then create a 1-inch notch at the base of the triangle. Roll the triangles up.
Refrigerate for 60 minutes up to overnight.
Preheat the oven to 400ºF.
Whisk an egg and brush it onto the exterior of each croissant.
Bake for 18-20 minutes until golden brown. Allow to cool.
Place 1 cup whipping cream and 2 tablespoons powdered sugar in a bowl and whip until stiff peaks form.
Wash and slice 8 oz of strawberries.
Slice the cooled croissants in half, and fill them with whipped cream and strawberries.
Serve immediately.