Toss fresh blueberries in a tablespoon of flour and freeze them for 30 minutes before folding into the batter to prevent sinking and ensure even distribution throughout each muffin.

Let eggs, Greek yogurt, and butter reach room temperature before mixing to create a smooth, homogeneous batter that bakes evenly and produces tender, fluffy muffins.

Mix wet and dry ingredients until just combined with visible flour streaks remaining; overmixing develops gluten and creates dense, tough muffins instead of light, tender ones.

Add fresh lemon zest along with the juice to intensify the citrus notes and brighten the berry flavor without making the muffins acidic or tart.

Keep butter cubed and ice-cold when making the crumb topping, using your fingertips to create pea-sized pieces that will bake into a golden, crispy texture instead of melting into a dense layer.