Preheat your waffle iron.
Meanwhile, combine the strawberries, lemon zest, and 1 teaspoon (4 grams) of sugar in a small bowl. Stir, and set aside.
Whisk the flour, baking powder, salt, and remaining 3 teaspoons (12 grams) sugar together in a medium bowl.
In a separate or measuring cup, beat the milk and egg together. Pour over the dry mixture, and stir with a fork until just combined.
Stir in the strawberries.
Using a rubber spatula, fold in the butter.
Let sit five minutes to “develop” (this allows the baking powder to activate).
Pour, or ladle, enough batter to cover about 2/3 of the surface (the rest will spread once you close the top). Cook according to the manufacturer’s directions. A sure sign of doneness is once you see all the steam has stopped shooting out the sides.
Serve hot with maple syrup, if desired.