8tablespoonsunsalted buttermelted and cooled, plus more butter for the pan
1 1/2cupsall-purpose flour
1firm but ripe nectarinecut into thin slices
4fresh figscut into eighths
Powdered sugarfor finishing
Preheat the oven to 350°F. Butter a 9-inch springform pan and coat with bread crumbs. In a bowl, using a handheld mixer, beat the granulated sugar and eggs at high speed until fluffy, 2 minutes. Beat in the butter. Zest the lemons and set aside 1/3 of the zest. Beat the remaining 2/3 into the batter.
Juice the lemons and remove seeds. At low speed, alternately beat in the flour and lemon juice until almost incorporated. Using a rubber spatula, gently fold the batter until smooth.
Scrape the batter into the prepared pan and smooth the surface. Gently press in the nectarine slices and figs. Bake the cake on the bottom third of the oven for 40 minutes. Transfer to the upper third of the oven and continue baking for 35 minutes longer, until a cake tester inserted in the center comes out clean with a few crumbs attached.
Transfer the cake to a rack to cool. Run a thin knife around the edge and release the springform. Dust the cake with powdered sugar. Sprinkle with the remaining lemon zest, cut into wedges and serve.