flesh of the peppers or eggplants is badly burned. The skins should blister and darken, but the flesh underneath should remain soft and flavorful.
Seeds and stubborn pieces of charred skin can also contribute bitterness, so remove them carefully.
### The mixture sticks to the pot
Use a heavy-bottomed pot and lower the heat. Stir more frequently, especially during the final hour when the mixture becomes thick.
### The texture is too smooth
Overprocessing can turn the vegetables into a thin purée. Pulse them briefly or use a meat grinder if you
