Heat a large skillet over medium-high heat until hot. Swirl in the avocado oil.: The moment you add the avocado oil you should hear a thin hiss and smell a light toasty note as the pan reaches cooking temperature, this signals the right heat for blistering the pods rather than steaming them. Use a skillet that conducts heat evenly so the peas cook consistently. A common mistake is not waiting for the skillet to be properly hot, which results in pale, limp peas rather than vibrant, blistered ones. If the oil smokes heavily, reduce the heat slightly to avoid burning the oil which will impart a bitter flavor. Keep a spatula ready to move the peas quickly across the pan to promote even charring.
Toss in the sugar snap peas and a 1/4 teaspoon Diamond Crystal kosher salt and cook, stirring frequently, until bright green, tender-crisp, and blistered in parts, about 2 minutes. Don’t overcook them!: As the sugar snap peas hit the hot oil you will hear sharp crackles, and the pods will go from dull to glossy bright green, with little blistered spots appearing where they contact the pan. This quick, high heat sear concentrates their sweetness while preserving snap. Pay attention to color changes more than the clock, because pan temperature varies. One pitfall is overcrowding the pan, which leads to steaming and a loss of char, so cook in a single layer and keep them moving for even contact.
Toss in the minced garlic and fish sauce and stir well, making sure the garlic doesn’t burn.: Right after the peas develop their blistered marks add the minced garlic and the fish sauce , you should immediately smell a savory, briny lift. The garlic will sizzle and release fragrant oils, so stir constantly to distribute heat and prevent charring. Burnt garlic tastes acrid and will overpower the dish, so once you sense the garlic aroma, be ready to move to the next step. The fish sauce will seem intense at first, but it merges with the peas and seasoning to provide depth.
Turn off the heat. Then, add the lime juice and toss well. Taste for seasoning and adjust with additional fish sauce or lime juice if needed.: With the heat off, pour in the lime juice so the citrus remains bright and aromatic rather than cooked away, you should hear a brief hiss as residual heat hits the liquid. Tossing now helps distribute acidity and balance the umami from the fish sauce . Pause and taste, seeking harmony between salty and tangy notes. A common error is overdoing either element, so add small increments when adjusting. If the dish tastes flat, a touch more salt or acid usually corrects it.
Transfer the snap peas to a serving platter. Scatter on the fresh herbs and crispy shallots and enjoy!: Moving the peas off the hot pan stops cooking so they keep their tender crisp texture; you will notice steam quickly rise but the pods will still have a lively snap. Scatter the chopped mint and Thai basil so their aroma remains vivid, and top with crispy shallots for crunchy contrast. Serve immediately, because the contrast between warm peas and fresh herbs is part of the appeal. A typical mistake is letting the shallots sit on the hot peas too long, which softens them, so add them just before serving.