Set oven to 425°F (218°C). Line a muffin tin with tulip paper liners.

In a small saucepan, combine blueberries, sugar, and lemon juice.

Cook over medium heat for about 5–7 minutes, stirring occasionally, until berries burst and the mixture thickens.

Remove from heat and cool.

Make the Crumble Topping

In a medium bowl, combine flour, brown sugar, granulated sugar, and cinnamon.

Add the cold butter cubes, and using a pastry cutter or your fingers, cut the butter into the mixture until coarse crumbs form.

Refrigerate while you prepare the muffin batter.

In a large bowl, whisk together flour, baking powder, and salt.

In another bowl, whisk together sugar, melted butter, eggs, vanilla bean paste, and milk until smooth.

Pour the wet ingredients into the dry and stir gently until just combined. Do not overmix — batter should be thick and slightly lumpy.

Gently fold in fresh blueberries.

Scoop batter evenly into muffin liners, filling about ¾ full. Leave 1–2 muffin wells empty and fill halfway with water to keep the muffins moist while baking.

Spoon 1–2 tablespoons of blueberry syrup onto the top of each muffin and lightly swirl it in.

Generously sprinkle each muffin with the crumble topping.

Bake at 425°F for 15 minutes.

Reduce heat to 325°F and continue baking for another 10 minutes, or until a toothpick inserted in the center comes out clean.

Allow muffins to cool in the pan for 5 minutes, then transfer to a wire rack. Serve warm or at room temperature with extra blueberry syrup drizzled on top if desired.