Remove the milk and butter from the refrigerator. Cut the butter into tablespoon cubes and set aside.

Spray a large mixing bowl with cooking spray and set aside.

In the work bowl of a stand mixer, add 3 ½ cups of flour. Add the sugar and salt on one side of the bowl. Stir the dry ingredients to combine.

If using instant yeast, add the yeast on the other side of the bowl and stir to combine. If using active dry yeast, proof yeast in water for 3 to 5 minutes and then add to the next step.

Pour the water and milk over the flour. Mix the dough on medium-high speed until smooth, about 8 to 10 minutes. Adjust dough consistency if necessary.

Form the dough into a smooth ball and place it in the prepared bowl. Cover with plastic wrap and let rest in a warm place for at least 30 minutes.

Clean the mixer bowl and attach the paddle attachment. Add the cubed butter and 2 tablespoons of flour and beat until smooth and creamy.

Shape the butter into a flat square using plastic wrap and chill in the refrigerator while the dough is proofing.

Once the dough has proofed, roll it into a rectangle, approximately 10-inch x 10-inch.

Place the butter square diagonally in the center of the dough and fold the corners over the butter, pinching to seal.

Refrigerate the dough for 60 minutes.

Roll the chilled dough into a 16-inch x 8-inch rectangle, folding into thirds like a letter. Refrigerate for 60 minutes.

Repeat the rolling, folding, and refrigerating process for a total of 3 turns, then wrap in plastic wrap and refrigerate overnight.

Roll the dough into a rectangle approximately 13-inch wide x 10-inch tall and about 1/4 inch thick. Trim edges to make them straight.

Cut croissant triangles using notches for guidance and roll from the wide end to the point.

Repeat for the other half of the dough.

Final proof shaped croissants on baking sheets for 60 to 90 minutes until doubled in size.

Preheat the oven to 375°F degrees.

Brush the beaten egg on each croissant and bake for 20 minutes, rotating pans halfway through. Transfer to a wire rack to cool.