These lemon poppy seed muffins are bakery style muffins with huge lemon flavour! They are filled with a sweet meringue filling that makes you think of lemon meringue pies!
Preheat oven to 350°F (180°C). Line a 12-cup muffin tin with cupcake liners, and set aside.
In a medium sized bowl, whisk flour, baking powder, baking soda, salt, and poppy seeds together. Set aside.
Add sugar, milk, lemon zest, lemon juice, and vanilla extract in a large bowl. Whisk to combine. Whisk in butter.
Add in dry ingredients and stir until combined. Don't overmix.
Divide batter evenly between the 12 muffin cups. Bake for 20-25 minutes or until a toothpick comes out clean.
Let muffins cool on a wire rack until fully cooled.
Meringue Filling
Add 2 inches of water to a small saucepan and bring it to a boil over medium heat.
Add sugar, cream of tartar, vanilla, and egg whites to a medium bowl, and place it over the saucepan with boiling water in it.
Whisk until the egg mixture reaches 160°F (71°C). Remove from heat and use an electric mixer or a stand mixer to beat it until stiff glossy peaks form.
Use a knife or the sharp end of a small piping tip to cut a hole in the bottom of a muffin about ½-inch deep. Keep the cored muffin piece to use as a "plug."
Use a pastry bag to pipe meringue filling into the muffin. Plug the hole up with some of the excess muffin. Repeat with all remaining muffins.
Store muffins in an airtight container in the refrigerator for up to 3 days.
Notes
Don't overmix the batter. This will cause gluten to over develop and will result in a tougher muffin. We want nice and tender muffins, so mix until the flour is just combined.
Let the muffins cool completely before filling with the meringue. If they are too warm, they will be difficult to handle, and the meringue would melt.
Want some more sweetness? A lemon glaze would be a nice addition. Mix together 1 cup powdered sugar and 1-3 tablespoons of lemon juice. Drizzle it over cooled muffins!
You can make the muffins the day before filling them. Store at room temperature in a air tight container.