In a large pot, heat the vegetable oil over medium heat.
Add the chopped onion and cook until softened and translucent.
Add the minced garlic and cook for an additional minute.
Stir in the chopped tomatoes and roasted red bell pepper.
Cook over medium heat, stirring occasionally, until the mixture starts to thicken (about 20-30 minutes).
Add the tomato paste, paprika, ground cumin, sugar, salt, and black pepper to the mixture.
Stir well to combine.
Continue cooking for another 20-30 minutes, stirring occasionally, until the lyutenitsa reaches a thick, spreadable consistency.
For a smoother texture, you can use an immersion blender to blend the mixture directly in the pot. Alternatively, allow the mixture to cool slightly and blend in batches using a regular blender.
Allow the lyutenitsa to cool to room temperature.
Transfer to sterilized jars and seal tightly.
Store in the refrigerator for up to 2 weeks or process in a water bath for longer shelf life.
Enjoy your meal!