In a saucepan over medium heat, warm the olive oil and sauté the minced garlic for about 1 minute until fragrant.
Add the canned diced tomatoes with their liquid to the pan, bring to a boil, then reduce to a simmer.
Season the sauce with 1 1/4 teaspoons dried oregano, 1/2 teaspoon salt, and 1/4 teaspoon black pepper; simmer gently for 10–15 minutes, stirring occasionally.
Preheat the oven to 375°F (190°C). Pour 1 cup of the sauce into the bottom of a 13 x 9-inch baking dish and set aside.
In a bowl, combine the ricotta, 1/2 cup grated Parmesan, 2 cups shredded part-skim mozzarella, 1/4 teaspoon black pepper, and 1 teaspoon dried oregano. Reserve 1/2 cup of this cheese mixture for topping.
Lay a boiled lasagna noodle flat, spread a portion of the cheese mixture evenly over it, drizzle about 1 tablespoon of sauce over the cheese, then roll the noodle tightly and place seam-side down in the prepared baking dish.
Repeat with the remaining noodles and cheese filling, arranging all rolls in the baking dish.
Pour 1 1/2 cups of sauce over the assembled rolls and sprinkle the reserved 1/2 cup cheese mixture on top.
Loosely cover the dish with foil and bake for 25–30 minutes, until the cheese is melted and bubbly.
Let the rolls rest for a few minutes before serving; serve remaining sauce on the side if desired.
