Make the pizza sauce: In a pot over medium-low heat, combine the crushed tomatoes and tomato puree. Add the oregano, Italian seasoning, garlic powder, onion powder, garlic salt, black pepper, and sugar. Stir everything together until well combined, and bring to a slight slow simmer. Taste and adjust seasonings if needed. Set aside.
Prep your puff pastry: Preheat your oven to 400°F (200°C). Unroll your thawed puff pastry sheet onto the prepared baking sheet. If there are any creases, gently smooth them out with your hands. I use a rolling pin to flatten it out a little more. Cut into 6 rectangles. Lightly score a ½-inch border around the edges without cutting all the way through. It gives you more of a "crust" result.
Add the sauce: Spread a generous layer of your homemade pizza sauce over the puff pastry, leaving about a half-inch border around the edges for the crust. Don't be shy with the sauce — you want good coverage!
Cheese it up: Sprinkle a generous amount of shredded mozzarella cheese all over the sauce. Again, don't hold back here. This is a judgment-free zone when it comes to cheese.
Pepperoni time: Arrange your pepperoni slices all over the cheese. You can overlap them, create patterns, or just scatter them randomly. There's no wrong way to pepperoni. Now use the beaten egg and a brush to give the crust an egg wash.
Bake to perfection: Pop the pizza into your preheated oven and bake for 18-20 minutes, or until the puff pastry is golden brown and puffed up, the cheese is melted and bubbly, and the pepperoni is starting to get crispy around the edges. (start checking on it at 15 minutes)
Cool slightly: Remove from the oven and let it cool for just a minute or two. This gives the cheese a chance to set slightly so it doesn't all slide off when you cut it.
Slice and serve: Cut into squares or strips, drizzle with homemade ranch (seriously, make the ranch), and devour immediately. Try not to burn your mouth in your enthusiasm.