Toss your blueberries with cornstarch and lemon juice before adding to the filling—this absorbs excess moisture and prevents the bars from becoming waterlogged while maintaining that juicy filling texture.

Lightly toast the rolled oats in a dry skillet for 2-3 minutes before mixing into your crust and topping. This brings out a rich, nutty flavor that elevates the entire bar.

Keep your butter cold and cut it into small cubes when making the crust and topping—this creates those desirable pockets that yield a tender, crumbly texture rather than a dense bar.

Reserve half your lemon zest to sprinkle on top just before baking so it doesn't lose its volatile oils and aromatic oils during cooking, delivering maximum citrus punch to each bite.

Refrigerate the baked bars for at least 2 hours before cutting—cold bars slice cleanly with distinct layers, preventing the filling from smearing and creating a more professional presentation.