In a large mixing bowl, whisk together flour, sugar, baking powder, cinnamon and salt. 

Use your fingers, to cut butter into dry mixture until butter is about pea-sized (a few larger chunks are ok). Fold in diced peaches. 

Drizzle over cold milk and vanilla extract. Use a wooden spoon or spatula to combine until the dough starts to come together. Once it gets too thick to stir with a spoon, use your hands to gently form it into a ball. Form and press dough into a mound. Do not over-knead or the scones will be dense. 

Tightly wrap in plastic wrap and refrigerate for 30 minutes.

To make streusel, in a mixing bowl combine oats, flour, brown sugar, salt, and cinnamon. Use your fingertips to pinch butter into dry mixture until thoroughly combined.

Preheat oven to 400°F. Line a baking sheet with parchment paper. Form dough into an 8" disc. Cut disc into 8 wedges.

Lightly whisk egg with 1 tsp water. Distribute on baking sheet and brush with egg wash and sprinkle over raw sugar. Top each scone with streusel, lightly pressing into dough to make sure it adheres. Bake for 18-20 min. or until tops are golden brown.

Make icing by whisking together all ingredients until desired consistency forms. Drizzle icing over cooled scones and enjoy.