Pre-heat ove to 350. Add lemon cake mix and lemon jello in a big mixing bowl. Beat in 4 eggs slowly to mix. Add milk, oil, and vanilla to mix. Cut lemon in half and squirt one half in the mix. Once the batter is thick, fill cupcake pan 2/3 of the way. Then drop 3 to 4 blueberries in each individual serving. Bake 10-15 min and enjoy!