1 med.-size lemon, well scrubbed and wiped dry
1/2 c. unsalted butter at room temp.
1 c. plus 4 tsp. granulated sugar
2 lg. eggs
1 tsp. baking soda
2 c. all-purpose flour
1 c. plain buttermilk or yogurt
3/4 c. (5 oz.) semi-sweet chocolate chips
1/4 c. fresh lemon juice

Heat oven to 375 degrees F. Grease 12 regular size or 24 miniature (1 3/4 inch diameter muffin cups) or line with foil or paper.