Prepare the PeppersWash banana peppers thoroughly. Wearing gloves, slice off the stems and cut into thin rings. Remove seeds for a milder flavor if desired.
Blanch the PeppersBring a pot of water to boil. Add sliced peppers and blanch for 2 minutes. Drain and set aside.
Sauté GarlicIn a large skillet, heat olive oil over medium heat. Add minced garlic and sauté until fragrant, about 1–2 minutes.
Combine IngredientsAdd blanched peppers to skillet. Stir in vinegar, oregano, salt, pepper, and sugar (if using). Cook for 5 minutes, stirring occasionally.
Cool and StoreRemove from heat and allow to cool. Transfer peppers and oil to sterilised jars, ensuring peppers are submerged. Seal tightly.
MarinateRefrigerate jars for at least 24 hours to allow flavors to meld. Store in fridge for up to 2 weeks.