Heat the oven to 375°F.

• Peel and thinly slice the onions.

In a pan over medium heat, warm 1 tablespoon oil until hot but not smoking. Add the onions, season with salt, and cook, stirring occasionally, until tender and browned, 16 to 18 minutes. While the onions cook, prepare the spread.

• Rinse the white beans.
• Zest and juice the lemon.
• Coarsely chop thyme leaves; discard the stems.
• Finely chop the garlic.

In a mixing bowl, combine the white beans, lemon zest, thyme, garlic, and ricotta with 1 to 2 teaspoons oil. Mash with a fork to make a coarse paste. Season to taste with salt and pepper.

• Pick the basil leaves from the stems and finely chop the leaves. Discard the stems.

In a small bowl, combine the basil, 2 tablespoons lemon juice, and 2 tablespoons oil. Season to taste with salt and pepper.

Arrange the flatbreads on a sheet pan. Spread the ricotta-bean mixture in an even layer on top, almost to the edges. Top with the onions and pine nuts, and drizzle with half the basil vinaigrette. Bake until well browned, 8 to 10 minutes.

Toss the mixed greens with the remaining basil vinaigrette. Cut the baked flatbreads into squares, top with the mixed greens, and serve warm.