Create the noodles using a spiralizer. If you don’t have one a mandoline or julienne tool also works Keep carrots separate from the zucchini.
If using a julienne tool only use the outside of the zucchinis. Save the inside of the zucchini to use in salads.
Heat the olive oil in a skillet over medium heat. Add the carrots and toss for 2 minutes until just softened.
Add zucchini and yellow squash. Cook until they just sort of relax into the pan instead of being so stiff, about 2 minutes. You don’t want them to be overly mushy but you also don’t want them to be hard and crunchy. Somewhere in between is perfect.
Add just enough to pesto to coat the noodles. Mix using tongs to spread everything evenly and to avoid clumps. Add more pesto if necessary.
Once the pesto is evenly distributed, serve, topped with red pepper flakes (optional).