• Cut the fennel lengthwise into quarters and cut away the core; thinly slice the quarters lengthwise.
• Strip the chard leaves from the stems; coarsely chop the leaves and stems, keeping them separate.
• Finely chop, press, or grate enough garlic to measure 2 teaspoons [4 tsp].
• Juice the lemon.
• Rinse the cannellini beans.

In a large sauce pot over medium heat, warm 1 to 2 tablespoons oil until hot but not smoking. Add the fennel and chard stems, season generously with salt and pepper, and cook, stirring occasionally, until the vegetables are starting to brown, 3 to 5 minutes. Stir in the garlic and cook until fragrant, about 30 seconds.
Add the chard leaves, vegetable broth, 2 tablespoons [¼ cup] lemon juice, and 2 to 3 cups [3 to 4 cups] water depending on your broth preference. Bring to a boil, reduce to a simmer, and cook, stirring occasionally, until the chard leaves are wilted, 3 to 5 minutes.
While the soup cooks, prepare the naan croutons.

In a large frying pan over medium heat, warm 2 to 3 tablespoons oil until hot but not smoking. Working in batches if needed, add the naan and cook, turning occasionally, until crisp, 4 to 6 minutes. Transfer to a cutting board to cool slightly, then cut into 1-inch pieces; season to taste with salt and pepper. Add more oil between batches if needed.
Alternatively, toast the naan in a toaster on a low setting several times until crisp, then season with salt and pepper and break into pieces.

To the pot with the soup, stir in the beans and cook over medium heat, stirring occasionally, until warmed through, 2 to 3 minutes. Remove from the heat and season to taste with salt and pepper.

Transfer the soup to individual bowls. Top each with 1 to 2 tablespoons basil pesto and the naan croutons. Serve any remaining pesto on the side.