PREPARE: Preheat the oven to 425 ̊F with a rack in the middle. Spray a 12-cup muffin pan with cooking spray or lightly coat with oil.
COMBINE DRY INGREDIENTS: In a large bowl, whisk together flour, baking powder and salt.
COMBINE THE WET INGREDIENTS: In a separate, medium bowl or mixer, beat together the sugar, zest,1 tablspoon of lemon juice, eggs, oil, milk and vanilla until smooth.
MIX ALL BATTER INGREDIENTS: With the mixer on low speed, add the dry ingredients to the egg mixture and stir until just combined. Using a spatula, fold fresh strawberries into the batter. Spoon the batter into each prepared muffin pan cup until three quarters full.
MAKE THE SWIRLED TOPS: In a small bowl, combine Preserves and remaining 1lemon juice. Spoon about 1 teaspoon of the strawberry preserve mixture into each muffin batter center, using a fork or toothpick, swirl the mixture into the lemon batter.
BAKE AND SERVE: Bake at 425˚until a toothpick inserted in the center comes out clean, 16 to 18 minutes. Let cool on a rack before serving.