01 - Preheat oven to 450°F. Place butter in an 8x8-inch baking dish and melt in oven for about 5 minutes while preheating.
02 - Remove dish from oven, swirl butter to coat bottom, then stir in peach preserves until combined with melted butter. Set aside.
03 - In large bowl, whisk together flour, baking powder, sugar, and salt until evenly distributed.
04 - Pour cold milk into flour mixture. Gently mix until just combined—do not overmix. Dough will be wet and shaggy.
05 - Pour biscuit dough directly over peach butter in baking dish. Carefully spread dough evenly to corners.
06 - Using lightly greased knife or bench scraper, score dough into 9 squares (3x3 grid) for easy 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.
09 - Remove biscuits from oven and cool for 10 minutes. Drizzle vanilla glaze generously over warm biscuits before serving.