In a small bowl, combine the warm milk and active dry yeast. Let it sit for about 5-10 minutes until it becomes frothy.
In a large mixing bowl, whisk together the unbleached all-purpose flour, sugar, and salt. Pour the yeast mixture into the flour mixture and stir until a dough begins to form.
Transfer your dough onto a lightly floured surface and knead it for about 5-7 minutes until it is smooth and elastic.
Place the kneaded dough into a lightly greased bowl and cover it with plastic wrap. Let it rise in a warm area for about 1 hour or until it doubles in size.
While the dough is rising, prepare the almond filling by blending blanched almonds, sugar, and a splash of almond extract until smooth.
Once the dough has risen, punch it down and transfer it to a floured surface. Roll the dough into a large rectangle, about 1/4 inch thick.
Cut the rectangle into triangles, approximately 4 inches wide at the base. Place a generous amount of almond filling at the base of each triangle.
Starting from the base, roll each triangle tightly towards the tip to form a crescent shape.
Place the rolled croissants on a baking sheet lined with parchment paper. Cover them with a kitchen towel and let them rise for another 30-45 minutes until puffy.
Preheat your oven to 375°F (190°C). Brush the tops of the croissants with an egg wash (beaten egg) and bake for 15-20 minutes or until golden brown.
Once baked, allow your almond croissants to cool slightly before serving. Dust with powdered sugar for an added touch of sweetness.