3 cups fresh basil leaves, tightly packed - divided
5 medium garlic cloves, peeled
9 green or red thai chiles, stemmed 0r 3 serranos or 1 medium jalapeno (I used 3/4 of a medium jalapeno to decrease spiciness)
3 Tbsp. fish sauce, divided
1 1/2 Tbsp. oyster sauce
1 1/2 tsp. white vinegar
1 1/2 Tbsp. sugar
1 1/2 lbs. boneless, skinless chicken breasts, cut in to 2" pieces
5 medium shallots, peeled and thinly sliced (about 1 1/3 cup)
3 Tbsp. vegetable oil
Red pepper flakes for serving, if desired
1. Process 1 1/2 cups basil leaves, garlic and chiles in food processor until finely chopped, 6-10 one second pulses, scraping down bowl with rubber spatula once during processing. Transfer 1 1/2 Tbsp. basil mixture to small bowl and stir in 1 1/2 Tbsp. fish sauce, oyster sauce, vinegar and sugar; set aside. Transfer remaining basil mixture to 12-inch heavy-bottomed nonstick skillet. Do not wash food processor bowl.
2. Pulse chicken and 1 1/2 Tbsp. fish sauce in food processor until meat is chopped into approximate 1/4-inch pieces, six to eight 1-second pulses. Transfer to medium bowl and refrigerate 15 minutes.
3. Stir shallots and oil into basil mixture in skillet. Heat over medium-low heat (mixture should start to sizzle after about 1 1/2 mins.; if it doesn't, adjust heat accordingly), stirring constantly, until garlic and shallots are golden brown, 5-8 minutes.
4. Add chicken, increase heat to medium, and cook, stirring and breaking up chicken with potato masher or rubber spatula, until only traces of pink remain, 2-4 minutes. Add reserved basil-fish sauce mixture and continue to cook, stirring constantly until chicken is no longer pink, about 1 minute. Stir in remaining cup basil leaves and cook, stirring constantly, until basil is wilted, 30-60 seconds. Serve immediately, passing extra fish sauce, sugar, red pepper flakes and vinegar to add as desired.
Serve with steamed rice and vegetables, if desired.
Complete all steps through step #3. Place cooked basil-shallot mixture in freezer bag and add uncooked chicken and freeze. Freeze reserved basil-fish sauce separately.
To cook from frozen:
Cut sauce out of bag prior to thawing. Thaw chicken mixture in refrigerator. Place in warmed non-stick skillet and follow instructions in step #4.