Place the peach slices between several layers of paper towels and pat dry them.
In a small bowl combine 1 cup of brown sugar with cinnamon and nutmeg, stir.
Fold the parchment paper in 3-4 layers, making a sling that is 3-4 inches wide. Make two if the slow cooker is over, not round.
Spray the ceramic insert of the slow cooker with cooking spray. Arrange the prepared parchment paper sling, placing it criss-cross on the bottom of a 6-quart oval/or round slow cooker, make sure its long enough to later lift the cake.
Next, add melted butter to the bottom. Sprinkle the brown sugar mixture on top.
Arrange peaches in a tight layer over brown sugar.
In a large bowl, beat softened butter with white and brown sugar until light and fluffy, about 3 minutes. Beat in eggs, 1 at a time, beating well after each addition. Beat in almond extract.
In a different bowl, whisk together flour, baking powder, and salt. Working in batches, stir in the flour mixture into the butter mixture alternating with milk, beginning and ending with the flour mixture. Mix batter until well combined, scraping the side and bottom of the bowl.
Spoon over the peaches and spread evenly.
Add a clean kitchen towel on top of the slow cooker and cover with the lid, the towel will absorb any condensation during baking.
Cook on High for 2 - 2 1/2 hours or until a wooden skewer inserted into the center of the cake comes out clean.
Once done, using oven mitts, remove the ceramic liner from the slow cooker and let the cake cool for 20 minutes. Run a knife around the edges of the cake and carefully lift with the parchment paper sling, or turn out onto a serving platter.
If desired top with simple powdered sugar and milk glaze.
Serve warm with vanilla ice cream.