Thaw the puff pastry sheets. Drain the Rotel. Finely chop the cilantro. Beat the egg if using. Measure out the cheese and whipped cream cheese.
Cook the beef
In a large skillet over medium heat, cook 1 pound ground beef until browned and cooked through. Drain the fat. Stir in 3 tablespoons taco seasoning and 10 oz Rotel. Cook for 2-3 minutes, then remove from heat. Mix in the chopped ½ cup cilantroand let cool slightly.
Prepare the pastry
On a lightly floured surface, unfold the 2 sheets refrigerated puff pastry. Roll each into a 12x10-inch rectangle. Spread 8 ounces whipped cream cheese evenly over each sheet.
Add the filling
Top each sheet with the ground beef mixture, spreading evenly. Sprinkle 1 cup Mexican blend shredded cheese on top of the beef.
Roll, chill, and slice
Roll each sheet tightly from the long side into a log. Wrap in plastic wrap and refrigerate for 1 hour. Remove from fridge, brush the outsides with beaten 1 egg, and slice each log into 12 pinwheels.
Bake
Preheat oven to 400°F (200°C). Place pinwheels on a parchment-lined baking sheet about 1 inch apart. Bake for 15-20 minutes until golden and bubbly.
Serve
Transfer to a serving platter and enjoy while warm.
Notes
Thawing Puff Pastry. Thaw the puff pastry in the refrigerator overnight or at room temperature for about 30 minutes. Make sure it's pliable but still cold.
Cutting the Pinwheels. Use a sharp, serrated knife to slice the pinwheels to prevent squashing the rolls.
Avoid Overfilling. Be careful not to overfill the pastry to ensure the pinwheels hold together while baking.