Mix butter, flour, sugar and salt in a small bowl until crumbly and well-combined.
Roll squares of cold cream cheese in 2 tbsp of sugar until coated on each side. Set aside until ready to use.
Pre-heat oven to 400ºF. Line a muffin tin with liners.
In a medium bowl, stir together flour, 3/4 c sugar, baking powder and baking soda. Cut in chilled butter and mix until crumbly in texture.
In a small bowl, blend the buttermilk and egg until mixed. Slowly combine with the flour mixture until just combined. Stir in chopped peaches.
Distribute evenly into the muffin tin.
Place one cube of cream cheese coated in sugar into the center of each muffin. Press until even with batter, but not submerged.
Bake for 20 to 25 minutes, or until a toothpick inserted off-center comes out clean.
Remove from the oven and cool in-pan on a wire rack for at least 10 minutes. Serve warm or at room temperature. Store leftovers in the refrigerator.