Place the brown rice noodles in a large bowl and cover with very hot water, soaking for 8-10 minutes until tender but firm, then drain and set aside.
In a small jar, whisk together the tamari, fish sauce, maple syrup, and lime juice to create the Pad Thai sauce.
Heat the avocado oil in a large skillet or wok over medium-high heat, then add the minced garlic and red pepper flakes, sautéing for 30 seconds until fragrant.
Add the shrimp to the skillet and cook for 2 minutes per side until pink and opaque, then push them to one side of the pan.
Crack the egg into the empty side of the pan and scramble quickly until just set, then mix it into the shrimp.
Add the drained noodles and the prepared sauce to the pan, tossing vigorously for 1-2 minutes to coat everything evenly.
Fold in the bean sprouts and green onions, cooking for just 30 seconds to retain their crunch.
Transfer to a plate and garnish with crushed peanuts and an extra squeeze of lime if desired.