In a stand mixer bowl, combine the flour, sugar, yeast, egg, egg yolk, and warm milk. Mix on low speed for 2-3 minutes.

Add the cubed butter and knead until the dough is soft and pliable, about 3-4 minutes. Transfer to a greased bowl, cover with plastic wrap, and let rise in a warm place for 1-2 hours until it doubles in size.

Preheat your oven to 375°F. Line a rimmed baking pan with parchment paper.

Once the dough has risen, turn it out onto a clean surface. Divide it into 8-12 equal pieces and roll each piece into a tight ball. Set them aside while you prepare the filling.

In a stand mixer, beat the softened cream cheese for 1-2 minutes until smooth. Add the powdered sugar, milk, and vanilla extract, and continue mixing for 2-3 minutes until the mixture is light and fluffy.

In a separate bowl, combine the brown sugar, flour, cinnamon, and melted butter. Stir until the mixture forms a crumbly texture.

Gently press your fingers around the edges of each dough ball to create a 1/2-inch circular edge. Stretch the center of the dough until it is about 1/4 inch thick, forming a ring. Place the dough rings onto the prepared baking pan.

Spoon the cream cheese filling into the centers of each ring, and top with the frozen blueberries. Brush the edges of the dough with the beaten egg, then sprinkle the coffee cake crumb mixture over the edges and center (optional).

Bake the danishes for 20-30 minutes, rotating the pan halfway through, until the edges are golden and the centers are set. Allow the danishes to cool for at least 10 minutes.

Whisk together the powdered sugar, vanilla extract, milk, and salt until smooth. Drizzle the glaze over the cooled danishes before serving.