Then, begin adding 1 Tbsp of flour at a time, stirring with a whisk to reduce clumps. I recommend starting with 2-3 Tbsp (as original recipe is written) and adding more later if needed. You can also thicken with extra parmesan cheese. Add salt, pepper, red pepper flake, pesto, cheese and stir.
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*Nutrition information is a rough estimate calculated with pasta.