Prepare blistered shishito sauce up to 5 days in advance. In a cast iron pan over high heat add shishito peppers to a tablespoon of oil, cook without stirring until beginning to blister, about a minute. Add sliced onion slices and stir fry until peppers are blistered, about 3-4 minutes. Then set aside and allow to cool slightly before cutting the stems off. Add cooled, stemmed blistered shishitos a food processor or high-powered blender with remaining sauce ingredients and process until smooth. Then transfer to jar or other lidded container, cover and refrigerate until ready to use.
4 cups shishito peppers, 1 medium white onion, 2 tablespoons canola oil, 2 cloves garlic, ⅛ teaspoon ground coriander, ⅛ teaspoon ground cumin, ¼ cup cilantro, ¼ cup flat leaf parsley, ½ cup chicken stock, 2 tablespoons white vinegar, 2 tablespoons lime juice, salt and pepper
When ready to cook, preheat oven to 325 degrees Fahrenheit and pat beef dry with paper towels. Season with salt and pepper. Place a large heavy bottom skillet or Dutch oven over medium-high heat and add 1 tablespoon oil. Once oil is shimmering carefully add half the beef in a single layer. Brown without stirring, for about a minute or two, then turn and continue to brown. Once meat is evenly seared remove to plate and repeat with another tablespoon of oil and remaining beef chunks, being careful not to cook the meat all the way through but only sear the outside.
Once all beef is browned and removed to plate, reduce heat to medium and add remaining tablespoon of oil, onions, garlic, and bell pepper. Cook until veg is beginning to soften, about 1-2 minutes then add tomatoes and herbs. Stir to cook slightly before carefully adding 1 cup shishito pepper sauce and stock. Bring mixture to a simmer, stirring to deglaze and pick up any browned bits on the bottom of the pan.
1 medium white onion, 1 medium bell pepper, 3 cloves garlic, 3 medium tomatoes, 1 cup blistered shishito pepper sauce, ½ cup chicken stock, ½ teaspoon dried marjoram, ½ teaspoon dried oregano, salt and pepper
Add browned beef back to pan and stir to coat. Cover and carefully transfer to preheated oven. Braise, covered, for an hour, then remove lid and sir and continue cooking uncovered until meat is fork tender and the sauce is succulent and rich, about 1 ½ to 2 hours longer.
Remove from oven and serve with remaining blistered shishito pepper sauce, garnished with fresh herbs and sliced shishito peppers.