Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.

Prepare the cream cheese mixture: In a small bowl, beat together the softened butter, granulated sugar, and softened cream cheese until smooth and creamy. Set aside.

Roll out the thawed puff pastry sheet gently on a lightly floured surface. Cut the sheet into 8 even squares (approximately 3.5 x 3.5 inches each).

Score the edges: On each square, lightly score a border about 1/2 inch from the edge using a knife, being careful not to cut all the way through. This will allow the edges to puff up higher.

Fill the centers: In a separate small bowl, mix the apricot preserves and lemon juice until slightly loosened. Spread a spoonful of the cream cheese mixture into the center of each pastry square, staying within the scored border. Top the cream cheese layer with about 1 teaspoon of the apricot mixture.

Bake the pastries: Brush the outer edges (the border) of each pastry lightly with the beaten egg wash. Bake for 18 to 20 minutes, or until the pastries are golden brown and fully puffed.

Prepare the optional glaze while the pastries cool slightly. Whisk together the powdered sugar and milk/water until you reach a thin drizzling consistency. Drizzle over the warm danishes.

Let cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely, or serve warm.