Preheat oven to 400
Whisk eggs, whole milk, melted butter, vanilla extract, and almond extract together in a mixing bowl
In a separate, large mixing bowl combine the brown sugar, white sugar, flour, and kosher salt
Add the wet ingredients to the dry ingredients in the large mixing bowl, and whisk them together to form a batter
Liberally coat a 12 inch cast iron skillet with butter, then pour the batter into the pan
Arrange the peach slices in an even layer on top of the batter. The peaches will settle to the bottom a little, which is okay. Dot in blueberries in any of the nooks and crannies between the peaches
Bake at 400 for 35-40 minutes. The flaugnarde should be puffed and golden and the middle set but still slightly wobbly.
Serve warm for dessert or for breakfast. If not eating right away, store in an airtight container in the refrigerator and reheat in the microwave for 30 seconds or so.
