While we recommend Yukon gold potatoes for their strong potato flavor you could also substitute with milder russet potatoes. The noodles are gluten-free, but the sauce is not; for a gluten-free version you can replace the soy sauce with tamari and check that your vinegar and bouillon powder are gluten-free as well. If gluten-free is important to you, be sure to read the labels on your ingredients to make sure they’re formulated and processed in a way that doesn’t introduce gluten. For a spicier sauce you can increase the crushed red pepper flakes to 2 tablespoons. Chinese sesame paste is made with roasted sesame seeds and can be purchased online or in Asian grocery stores; tahini is a good substitute but will have a milder sesame flavor since it’s made with raw, not roasted, sesame seeds.