Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.

Combine flour, baking powder, baking soda, salt, and cinnamon in a bowl.

Cream the butter with granulated and brown sugar in a mixing bowl until fluffy.

Add the egg and vanilla, mixing until smooth.

Alternate adding dry mixture and buttermilk into the butter mixture, mixing until combined.

Fold in the finely diced peaches gently with a spatula.

Scoop mounds of batter onto the baking sheets, keeping 2 inches apart.

Bake for 10-12 minutes, until edges are golden. Let cool for 5 minutes before transferring to a wire rack.

Prepare the cream filling by beating cream cheese and butter until smooth. Gradually add sugar, vanilla, and heavy cream.

Assemble the whoopie pies by pairing cookies and filling them generously.

Chill in the fridge for at least 15 minutes before serving.