Preheat oven to 325°F (165°C) and grease and flour a bundt or loaf pan

Combine peaches, brown sugar, cinnamon, lemon juice, and cornstarch; toss well and set aside

Cream butter and granulated sugar until light and fluffy

Add eggs one at a time, mixing well after each

Mix in sour cream and vanilla

Gradually add flour and salt, mixing just until smooth

Stir together brown sugar and cinnamon for the swirl

Spread half the batter into prepared pan

Sprinkle half the cinnamon sugar over batter

Spoon peach mixture evenly on top

Add remaining batter and finish with remaining cinnamon sugar

Bake for 75–85 minutes, tenting loosely with foil if browning too quickly

Test doneness with a skewer; it should come out mostly clean

Cool in pan for 20 minutes, then turn out and cool completely