Set an oven rack about 6 inches from the heat source and preheat the oven's broiler. Line a baking sheet with aluminum foil.

Arrange chile peppers on the prepared baking sheet.

Cook under the preheated broiler until pepper skins blackened and blistered, 5 to 8 minutes.

Transfer chile peppers to a bowl; tightly seal with plastic wrap and steam until cool, about 20 minutes. Remove and discard chile pepper skins.

Combine chile peppers, diced tomatoes, diced tomatoes with roasted garlic, onion, cilantro, and garlic powder in the bowl of a food processor or blender; pulse until reaches desired consistency.