Pulse the chopped basil, oregano, garlic, olive oil, and red pepper flakes in a food processor until a coarse paste forms.

Toss the eggplant with a teaspoon of salt in a large microwave-safe bowl. Cover and microwave until the eggplant has collapsed and softened, about 6 to 10 minutes—this step removes excess moisture so the stew base stays concentrated.

Heat the olive oil in a Dutch oven over medium-high heat until it shimmers. Add the microwaved eggplant, onion, and potatoes and cook, stirring occasionally, until the vegetables are softened and the eggplant begins to brown, about 10 minutes.

Stir in the tomato paste and cook until it darkens in color and a flavorful brown film forms on the bottom of the pot, about 2 minutes.

Stir in the water, chopped tomatoes, and reserved tomato juice. Bring to a simmer, then reduce the heat to medium-low and cook until the eggplant has mostly broken down into the sauce and the potatoes are tender, 25 to 30 minutes.

While the stew simmers, place the zucchini and bell peppers in a large skillet over medium-high heat. Cook until the vegetables are browned and any liquid they release has completely evaporated, about 10 minutes.

Remove the skillet from the heat and stir the pesto into the hot zucchini and peppers. Fold the pesto-coated vegetables into the Dutch oven and simmer for 5 minutes to let the flavors meld.

Remove the pot from the heat and stir in the shredded basil. Serve hot, ideally with thick slices of crusty bread for dipping.