Preheat your oven to 350°F and line a muffin tin.
Start by making the blueberry jam. Add the blueberries and sugar to a small saucepan over medium heat. Cook for about 15 minutes, stirring every few minutes, until thickened. Remove from heat and set aside to cool.
In a bowl or stand mixer, beat the cream cheese, sugar, and egg yolk on high speed for 2–3 minutes until smooth and creamy. Transfer to a piping bag or set aside.
In a large bowl, mix together melted butter, brown sugar, and granulated sugar until combined. Add the eggs and vanilla and mix until smooth, then stir in the milk and yogurt.
Add the flour, baking powder, cornstarch, and salt, mixing until just combined.
For the crumble, mix together melted butter, sugar, and flour using your hands until crumbly.
Scoop the muffin batter into your prepared pan. Add a spoonful or pipe the cream cheese filling into the center of each muffin, followed by a spoonful of blueberry jam.
Top generously with crumble.
Bake for 26–28 minutes, until golden and set.
Let cool for about 20 minutes, then enjoy every soft, creamy, jam-filled bite 🫐🤍
