Preheat your oven to 350°F (175°C). Grease a 9-inch round cake pan or an 8×8 square pan with butter or neutral oil and dust lightly with flour, or line with parchment for easy release.

Peel and chop the peaches into small, even pieces (about 1/2-inch). Place them in a bowl and drain any excess juice; reserve a tablespoon if you want to fold a tiny bit into the batter for extra peach intensity.

In a mixing bowl, beat the 3 large eggs until lightly frothy, then whisk in 1/2 cup peach nectar or juice and vanilla if using.

Gently fold the chopped peaches and 1/2 cup heavy cream into the egg-nectar mixture.

In another bowl, combine 1 cup packed brown sugar; then add it to the wet mixture and stir until mostly dissolved.

Whisk together 1 3/4 to 2 cups all-purpose flour, 2 teaspoons baking powder, and 1/4 to 1/2 teaspoon salt. Gently fold the dry mix into the wet ingredients until just combined—don’t overmix.

The batter should be thick but pourable; if it seems too tight, add a tablespoon of peach nectar or cream. If too loose, add a tablespoon of flour at a time.

Pour the batter into the prepared pan and smooth the top gently with a spatula. Scatter any extra peach slices, a light dusting of cinnamon, or nuts on top if using.

Bake at 350°F (175°C) for 30–40 minutes, checking at the 30-minute mark with a toothpick.

Let the cake cool in the pan for 10–15 minutes to set, then run a thin knife around the edges and transfer to a cooling rack or plate.

Serve warm or at room temperature. Finish with powdered sugar, a light caramel drizzle, or a scoop of vanilla ice cream or whipped cream.