Follow these simple steps to create your Peach Upside Down Cake:

1. Preheat Oven: Preheat your oven to 350°F (175°C). Grease a 9-inch round cake pan.
2. Prepare Peaches: In a saucepan over medium heat, melt the butter. Add the brown sugar and stir until combined. Remove from heat and pour the mixture into the bottom of the prepared cake pan.
3. Arrange Peaches: Place the sliced peaches over the brown sugar mixture in the pan, arranging them in a circular pattern.
4. Mix Dry Ingredients: In a large bowl, whisk together the flour, granulated sugar, baking powder, and salt.
5. Combine Wet Ingredients: In another bowl, beat together the eggs, milk, and vanilla extract until well combined.
6. Combine Mixtures: Gradually add the wet ingredients to the dry ingredients, mixing until just combined and smooth.
7. Pour Batter: Carefully pour the batter over the arranged peaches in the cake pan.
8. Bake: Place the pan in the preheated oven and bake for 40-45 minutes or until a toothpick inserted into the center comes out clean.
9. Cool: Once baked, remove the cake from the oven and allow it to cool in the pan for about 15-20 minutes.
10. Invert Cake: Carefully invert the cake onto a serving plate while it is still warm, so the peaches are on top.

These steps will guide you in creating this incredible dessert that your friends and family will love.