Preheat oven to 350°F. Line a 15x10x1-inch baking pan with parchment paper; set aside.

Trim a very thin slice from the round side of each peach half so halves stand flat on the baking pan. Dip peach halves in melted butter to coat. Arrange peach halves, cut sides up, in prepared pan. Sprinkle cut sides of peaches with cinnamon-sugar; set aside.

In a medium mixing bowl beat cream cheese with a mixer on medium speed until smooth. Add sugar, egg yolk, and vanilla. Beat until combined. Spoon cream cheese mixture into peach centers.

Bake, uncovered, about 30 minutes or until lightly browned and softened. Serve warm or at room temperature.