1. Prepare the peaches: Reserve 2 Tablespoons of peach juice from the cans for the muffin batter, then drain the peaches. Chop enough peaches into small 1/3-inch pieces to make 1 heaping cup for the batter. Chop additional peaches into slightly larger pieces, about 1/2 inch, to sprinkle on top. You will need about 3/4–1 cup for the topping, and may have some peaches left over.

To Make the Streusel

1. Using a fork, whisk 1/3 cup of granulated sugar and 3/4 cup of flour together. Add cinnamon if desired. Pour in the melted butter and mix with a fork until evenly moistened and coarse crumbs form. Refrigerate until ready to use.

To Make the Cream Cheese Filling

1. Mix the softened cream cheese, 1/3 cup of sugar, and vanilla until smooth. Set aside. The mixture does not need to be whipped until fluffy; simply combine the ingredients.

To Make the Peach Muffin Mixture

1. Preheat the oven to 425°F. Line a standard muffin pan with paper liners and set aside.
2. In a large mixing bowl, whisk together the eggs, sugar, reserved peach juice, milk, vanilla, and melted butter.
3. Sift in the all-purpose flour, baking powder, and salt. Whisk to combine.
4. Toss 1 cup of the small diced peaches with 1 Tablespoon of flour. Gently fold the peaches into the muffin mixture using a rubber spatula.

To Assemble the Muffins

1. Spread about 2 1/2 Tablespoons of batter into the bottom of each paper liner. Add about 2–3 teaspoons of cream cheese filling in the center. Spread about 1 Tablespoon of muffin batter over the filling. Each cup should be about 2/3 to 3/4 full. Add a few pieces of chopped peaches on top and sprinkle with streusel crumbs.
2. Place the muffin pan on a baking sheet and put it in the oven. Bake for 5 minutes at 425°F, then reduce the oven temperature to 350°F and bake for 20–25 minutes. Cool in the pan for 5 minutes, then transfer the muffins to a rack to cool completely.
3. Store at room temperature for up to 1 day, then refrigerate in an airtight container for 3–4 days.