Preheat oven to 375°F. Lightly coat cups of a 12-cup muffin tin with cooking oil spray (or use muff in cup liners or silicone cups).

Add lime zest and sugar to a small bowl. With your fingers, rub zest into sugar to infuse sugar with lime flavor. In a large bowl, vigorously stir butter and lime zest sugar with a wooden spoon until the mixture is well combined. Add eggs, one at a time, stirring after each until eggs are thoroughly incorporated. Add lemon purée and stir to combine.

Combine baking powder and flour in a small bowl. Alternate adding flour mixture and milk to the butter-sugar mixture, stirring aft er each addition until nearly combined.

Fold in blueberries until combined. Scoop ⅓ cup of batter into each muffin cup (or use an ice cream scoop). Sprinkle each muff in with 1 teaspoon of crystallized sugar, if using.

Bake for about 30 minutes, or until the edges of muffins are browned and a toothpick comes out clean when inserted into muffin. (Start checking the muffins at 25 minutes.)

This purée is the perfect addition to desserts when you want a concentrated lemon flavor without the tartness of lemon juice. Adjust the flavor by adding more lemon juice or brine—it’s up to you.

Makes approximately ½ cup

Add lemon rind and brine to bowl of a small food processor and pulse a few times to break down rind. Add remaining ingredients and pulse to purée. Mixture can be left slightly chunky or puréed until smooth.

Store purée in an airtight container in the fridge for up to 2 weeks.

Cool on a baking rack for 10 minutes. Remove muffins and let cool completely.

Store in an airtight container or freeze for longer storage.