In a small bowl, combine warm milk, sugar, and yeast. Let sit 5–10 minutes until foamy.

In a stand mixer bowl, combine bread flour, all-purpose flour, and salt.

Add yeast mixture and cold water. Mix until a shaggy dough forms.

Add softened butter and knead 6–8 minutes until smooth and slightly tacky.

Cover and let rest 1 hour until slightly puffy.

Shape dough into an 8x10-inch rectangle, wrap tightly, and refrigerate 1–2 hours.

Place butter between parchment paper and pound or roll into an 8x5-inch rectangle (making sure it all sticks are well combined).

Chill until firm but pliable. Butter should match the consistency of the dough. (If it is alittle too firm when removing from the fridge, use the rolling pin to gently pound it to soften it up)

Roll chilled dough into an 8½x12-inch rectangle. Place butter in the center and fold dough over to fully enclose. Seal edges.

Roll into an 8x24-inch rectangle. Fold into thirds like a letter, wrap, and chill for 30–45 minutes.

After final fold, chill at least 1 hour or overnight (up to 24 hours).

Roll dough into a 10x24-inch rectangle, about ⅛-inch thick. Trim edges.

Cut triangles with a 4-inch base and about 8-inch height.

Gently stretch each triangle, then roll from base to tip. Curve ends slightly inward.

Place on parchment-lined baking sheets.

Let croissants proof at 70–75°F for 2–3 hours, until puffy and slightly jiggly. (This may take longer, or shorter, depending on the temperature of your kitchen.)

Whisk egg and cream, then brush croissants evenly.

Cool for 10 minutes before serving.