Preheat the oven to 375°F. Add the cherry tomatoes, oregano, and garlic to a large 10” cast-iron skillet. Cover with the olive oil, and season with the salt & lots of freshly cracked black pepper. Toss to combine. Roast for 45 minutes to 1 hour, or until the tomatoes are soft and caramelized.
Meanwhile, add the cubed baguette to a food processor. Pulse until finely chopped. Heat a 12″ stainless steel skillet over medium heat and add enough olive oil to cover the bottom. Once hot, add the breadcrumbs. Toast for about 6 minutes until golden and crisp, stirring often (lower the heat if needed so they don’t burn). Stir in the chopped fresh herbs. Season with a good pinch of salt. Transfer the breadcrumbs to a plate lined with a paper towel to drain.
Bring a large pot of salted water to a boil. When the tomatoes have about 5 minutes of roasting left, drop the fettuccine. Stir well and cook for 1 minute less than the package’s instructions.
Remove the roasted tomatoes from the oven and let cool for a minute or so. Discard the oregano sprigs. Transfer the entire mixture to a blender. Add the basil. Add 1 cup of starchy pasta water from the pasta pot. Blend until smooth.
Drain the pasta and add it back to the pot. Pour in the creamy tomato sauce and stir really well to combine. Add the mascarpone and parmesan cheeses. Over low heat, stir until the cheeses have melted and the sauce clings to the pasta. Taste the pasta and season with more salt if needed.
Serve the pasta with the herb breadcrumbs and extra fresh herbs over top.