Preheat oven to 350°F. Line 24 muffin cups with paper liners.
In a measuring cup, combine lemon juice with enough milk to make 1 cup. Let sit 5 minutes.
In a large bowl, cream butter and sugar until light and fluffy.
Beat in eggs one at a time. Add lemon extract and zest.
Stir in the soured milk, then fold in chopped strawberries.
In another bowl, whisk together flour, baking powder, baking soda, and salt.
Add dry ingredients to the wet mixture and stir until just moistened.
Fold in chocolate chips, if using.
Spoon batter into muffin cups, filling each about 2/3 full.
Top each muffin with a strawberry slice and sprinkle with a little sugar.
Bake 25–30 minutes or until a toothpick comes out clean.
Cool in pans for 5 minutes, then transfer to wire racks.