01 - Preheat oven to 450°F. Place butter in an 8x8-inch baking dish and put in oven to melt while preheating, approximately 5 minutes.
02 - Remove dish from oven, swirl to coat bottom evenly, and stir in peach preserves until fully combined with melted butter. Set aside.
03 - In large bowl, whisk together flour, baking powder, sugar, and salt until thoroughly blended.
04 - Pour cold milk into dry ingredients and gently mix until just combined. Do not overmix; batter will remain wet and shaggy.
05 - Pour biscuit dough directly over peach butter in baking dish. Carefully spread dough evenly to corners using spatula.
06 - Using lightly greased knife or bench scraper, score dough into 9 equal squares (3x3 grid) to facilitate separation after baking.
07 - Bake for 22-25 minutes until top is golden brown and center is set.
08 - While biscuits bake, whisk together powdered sugar, milk, and vanilla extract until smooth and pourable consistency is achieved.
09 - Remove biscuits from oven and cool for 10 minutes. Drizzle vanilla glaze generously over warm biscuits before serving.