Heat a saute pan over high heat, and add olive oil. When the pan is hot, add shishito peppers; cook turning occasionally until blistered in spots. Be careful peppers might pop. Remove from heat.
When peppers are cool enough to handle, cut to discard the stem and place peppers in container of food processor or electric blender. Add shiso leaves, garlic clove, lemon juice, olive oil, salt, and pepper; cover and process until finely chopped and everything blended, scraping the side as necessary. Scrape off the mixture from the container into a bowl; mix minced shallots. Season to taste with salt and black pepper if needed.
