In a large pot of boiling salted water, cook fettuccine, stirring occasionally, until very al dente, about 1 minute less than package instructions. Reserve 1/2 cup pasta water. Drain pasta and transfer to a large bowl. Add oil and toss to combine.
Meanwhile, in a blender or food processor, pulse cottage cheese, milk, Parmesan, garlic, butter, flour, and 1 teaspoon salt until smooth. Transfer sauce to a large skillet. Bring to a simmer over medium heat and cook, stirring frequently with a heatproof spatula, until thickened, 8 to 10 minutes. Add spinach and stir until wilted.
Add pasta to skillet and toss in sauce to coat, using pasta water to loosen sauce if it becomes too thick.
Divide pasta among bowls. Top with red pepper.
Recipe Notes
I would give credit to the website that published this recipe but they put it behind a pay wall so fuck them