Whisk together the flour, baking powder, sugar, and salt.
Cut the butter into chunks and mix into the flour mixture by hand until the butter is about the size of peas. Mix in milk. Set aside.
Mix together the peaches, granulated sugar, and cinnamon.
Chunk the biscuit dough into small pieces (you can just rip it!). Mix in the peaches. Dump into a bundt pan.
Melt the butter and whisk in the brown sugar. Pour over the peaches and biscuit dough.
Bake at 350F for 35-40 minutes.