In bowl of electric mixer cream butter and sugar until smooth. Add cottage cheese.
Add eggs, one at a time, beating well after each addition.
Add lemon extract and beat until combined.
In a large bowl combine flour, baking powder, baking soda, salt and lemon zest, stirring with a spatula until combined.
Add wet ingredients to dry and stir just until combined. Fold in chocolate chips.
Scoop batter into muffin pans sprayed with cooking spray. Fill almost to the top for larger muffins or 2/3 full for regular sized muffins. Sprinkle with course sugar.
Bake for 20-24 minutes, check for doneness after 20 minutes.
Muffins are done when a toothpick inserted in the centre comes out clean.
Notes
Store in an airtight container lined with paper towel for up to 3 days.