01 -
In a bowl, stir together the yeast, warm milk, and sugar. Leave it untouched for 5-10 minutes until it gets bubbly. Add vanilla, melted butter, salt, and an egg. Slowly mix in the flour until you get dough. Knead it for 8-10 minutes until it's stretchy and smooth. Cover with a towel and place somewhere warm for 1-1.5 hours until it doubles in size.
02 -
Combine cornstarch, blueberries, and sugar in a bowl. Toss them together and set the bowl aside.
03 -
Set your oven to 375°F (190°C) and line a baking tray with parchment paper. Punch down the dough and split it into 10-12 pieces. Flatten each one into a disc, put a spoonful of blueberry mix in the middle, and pinch the edges shut. Lay the buns seam-side down on the tray.
04 -
Use your fingers to rub together butter, flour, and sugar in a bowl until it feels crumbly. Brush the buns with some milk or egg wash, then sprinkle the streusel on top. Bake for 18-22 minutes until they're golden brown. Let the buns cool a bit before digging in.