Cut puff pastry dough into squares about 3×3 inches large and gently press each square into a lightly greased muffin tin. Set aside.
Use a hand mixer to whip together the cream cheese, shredded cheddar, jalapeno, salt, black pepper, and garlic powder until smooth and slightly fluffy.
Add filling to the prepared puff pastry cups. Place 2 sausage slices to each, then fold the corners of the dough squares to meet in the middle.
Mix together the egg with 1 tbsp water, then brush it over the tops of the pastry bites.
Bake the pastry bites until golden and flakey (about 25-30 minutes).