[Optional] To make the shrimp crunchy and snappy:

• Soak the shrimp in a large bowl with cold water and baking soda. Gently message and chill the bowl in the fridge for at least 30 minutes and up to a night before. Discard the water and rinse the shrimp a few times then pat them dry.
• Thinly slice the garlic, onion, finely chop the ginger, and slice the green onions into 1.5-inch sections and separate the white and green parts. Set aside the Sha cha stir fry sauce in a small bowl.
• [Optional] Butterfly the shrimp on the back side by making a shallow slit, using a small paring knife. In a large bowl, toss the shrimp with starch and coat it well on all sides.
• Preheat a large non-stick saute pan over medium heat until it feels hot then add 1 tbsp oil. Add the shrimp and spread them out into a single layer. A slight overlap is okay. Pan fry the shrimp over medium to medium-high heat for 2 minutes on the first side and 2 minutes on the flip side. Transfer them out and set aside.
• Use the same pan, add the remaining half tablespoon of oil. Saute the garlic, ginger, white scallion parts, and onion with a pinch of salt over medium heat for 10 seconds. Toss in the cashew nuts and keep tossing and stir-frying for 10 more sections.
• Return the shrimp and the green scallion parts to the pan. Pour in the sauce. Turn heat up to medium-high. Add a small splash of Taiwanese michu, if using. Give everything a quick toss for about 15 seconds then turn off the heat. Transfer the shrimp to a serving plate. Serve hot with rice.