To a small blender or small food processor (or in a large food processor if making a double batch) add bell pepper, garlic, red pepper flakes, maple syrup, salt, apple cider vinegar, and habanero (optional).
Option to briefly cook tomato paste in a small metal or non-stick pan over medium-low heat for 5 minutes, stirring frequently, to slightly reduce the raw tomato flavor. Otherwise, add to the blender or food processor, no cooking required.
Blend until well mixed, then taste and adjust flavor as needed, adding more tomato paste for depth of flavor / tomato flavor, salt to taste, red pepper flake or habanero for heat, maple syrup for sweetness / to balance the flavors, or vinegar for acidity. We added a bit more red pepper flake and salt.
Use immediately, or store covered in the refrigerator for up to 7 days, sometimes longer (discard when the flavor or appearance appears off). Note that the color deepens and the texture thickens after refrigerating overnight. Option to freeze leftovers into ice cube molds to use as needed (store in a sealed container in the freezer for up to 3-6 months).
*Recipe as written makes ~3/4 cup or 200 ml sriracha. *Nutrition information is a rough estimate calculated without optional ingredients. *Inspiration from Steamy Kitchen.