Preheat oven to 325 F and line 3 8-inch cake rounds with parchment paper and nonstick spray.

In a large mixing bowl or a stand mixer with the paddle attachment add the butter, and oil. Cream butter, oil and then add in the eggs, sour cream, vanilla extract, and mix until all the ingredients are combined.

Add the dry ingredients (flour, baking soda, baking powder, salt, cinnamon and sugar) to the wet ingredients, mix until just combined, and then scrape the sides and bottom of the bowl with a rubber spatula.

Heat the milk mixture until hot and then pour it into the cake batter. The cake batter should be thin.

Divide batter into three cake pans and bake the cakes in the preheated oven for 18 to 24 minutes. Insert a toothpick into the center of the cakes to check if it’s clean, once the cakes are done baking allow them too fully cool.

Allow the cake to cool on a wire rack until needed.

Wash and peel the skin of the peaches and then chop the peaches into 1–2-inch pieces.

In a medium saucepan, combine the chopped peaches, butter and sugar over medium heat.

Let them cook for about 5-7 minutes until the peaches begin to release their juices and soften.

Mix the cornstarch with water to create a slurry. Stir this into the simmering peaches and mix it in.

Continue to cook for just a couple more seconds, stirring frequently, until the compote thickens. Remove from heat.

Let the compote cool completely before transferring it to an airtight container. It can be refrigerated and prepped ahead up to a week.

In a heatproof bowl combine the egg whites and brown sugar.

Place the bowl over a pot of simmering water (double boiler) and whisk constantly until the sugar has completely dissolved and the mixture reaches 160F.

Transfer the egg white mixture to your stand mixer fitted with the whisk attachment (or use a hand mixer) and whip on high speed until stiff peaks form and the meringue is glossy. This process usually takes about 10-15 minutes.

Once the meringue bowl is cool to touch slowly start adding in the butter 1 stick at a time and then add in the vanilla. The buttercream might look curdled but don't worry just keep letting it mix for another 10 minutes on medium speed.

Switch the whisk to a paddle attachment and mix on low speed for 10 to 15 minutes to release the air bubbles.

If the buttercream is soupy chill frosting for 30 minutes in the refrigerator and then try to whip it again.

Take a serrated knife and cut the tops of the cakes off to have a leveled cake.

Place a cake layer on a cake stand or serving plate. Fill a large piping bag with the brown sugar frosting and pipe a frosting border of the brown sugar frosting on the outer edges of the cake and fill the inside with half of the peach filling.

Top with the second layer and repeat until the third layer.

Spread a thin layer of frosting on top of the cake and sides and then refrigerate for 20 minutes to let the cake set (crumb coat). Spread the rest of the frosting on the Brown sugar peach cake and then garnish the top with additional fresh sliced peaches.

Refrigerate the cake for 1 hour if time allows before serving and for best results consume the next day to allow the cake layers to soak up all the flavors.