Place the brown rice noodles in a large bowl and cover with very hot water, soaking for 8 to 10 minutes until tender but firm, then drain and set aside.
In a small jar, whisk together the tamari, lime juice, maple syrup, and red pepper flakes to create the pad thai sauce.
Heat the avocado oil in a large skillet or wok over medium-high heat, then add the shrimp and minced garlic, sautéing for 2 to 3 minutes until the shrimp are pink and opaque.
Push the shrimp to one side of the skillet, crack the egg into the empty space, and scramble quickly until just set.
Add the drained noodles and the prepared sauce to the skillet, tossing everything together for 1 to 2 minutes until the noodles are well-coated and heated through.
Fold in the mung bean sprouts and chopped green onions, cooking for just 30 seconds to maintain their crunch.
Garnish with crushed peanuts and an extra squeeze of lime before serving warm.