Preheat the oven to 400° F. Line a baking sheet with a silpat (see note) or parchment paper. Set aside.
In a large bowl, combine flour, brown sugar, baking powder, and salt. Stir to combine.
Add the cold, cubed butter to the mixture. Using a pastry blender (see note) or two forks, cut the butter into the dry ingredients until the butter is pea-sized and smaller. Set aside.
In a small bowl, whisk together egg, heavy cream, sour cream, and vanilla bean paste (see note). Pour over the flour/butter mixture and mix, stopping just before completely combined. Add the diced peaches and gently mix in until incorporated.
Turn the dough out onto the prepared pan. Pat the dough into a circle about ½" thick. Cut the round into 8 triangles.
For Streusel:
In a small bowl, combine flour, sugar, brown sugar, and salt. Mix to combine. Add softened butter and mix/cut in until clumps form.
Brush the tops of the scones with cream, then top with the streusel (it will seem like a lot, but use all of it!). Bake 18-20 minutes, or until golden. Allow to cool on a wire rack. You will need to cut again into triangles before serving.
For Glaze:
Combine all glaze ingredients in a small bowl, mixing until smooth. Spoon over the cooled scones, or pour the glaze into a zip-top bag, cut the corner, and pipe on top of each scone. Allow the glaze to set before serving.Enjoy!
Notes
Note on vanilla bean paste: I just love the extra punch of vanilla flavor from vanilla bean paste! You can find it online [here], or substitute an equal measure of vanilla extract if you prefer.Note on silpat: I like baking the scones on a silpat for ease of cleanup and because they can be used over and over again. If you're interested in getting one for yourself, you can find one [here].Note on pastry blender: While a pastry blender isn't necessary to cut in the butter, it does make the job a lot faster and easier. If you're looking to buy one for yourself, you can find one [here].