01 -
In a medium bowl, sift together the flour, baking powder, baking soda, salt, and poppy seeds. Set aside.
02 -
In a separate large bowl, whisk together the melted butter, sugar, eggs, vanilla, lemon zest, lemon juice, sour cream, and milk. The mixture will be a little lumpy because of the sour cream.
03 -
Add the dry ingredients to the wet ingredients and mix together using a rubber spatula. Mix until just combined - do not overmix.
04 -
Preheat the oven to 425°F. Line a 12-cup muffin pan with 6 muffin liners, leaving a space between each liner (this helps the muffins rise taller). Let the muffin batter sit for 15 minutes before scooping.
05 -
While the batter rests, make the filling. In a medium bowl using a hand mixer, beat the cream cheese and sugar on high speed until smooth. Add the milk, flour, and vanilla, then mix on medium speed until combined. Scoop the cream cheese filling into a piping bag and cut ½ inch off the tip.
06 -
In a small bowl, mix the lemon zest and sugar. Use your fingers to press the zest and sugar together, releasing the oils from the zest. Set aside.
07 -
Use a large cookie scoop (2-3 tablespoons) to fill each muffin liner about ¾ full with batter. Insert the tip of the piping bag about ½ inch into the batter and squeeze until a small dollop of filling appears on top. Sprinkle the lemon sugar generously over each muffin.
08 -
Bake for 8 minutes at 425°F, then reduce the oven temperature to 350°F (without opening the oven door) and continue baking for 6-8 more minutes. Muffins are done when a toothpick inserted comes out clean.
09 -
Let the muffins cool in the pan for 10 minutes before transferring to a wire cooling rack to cool completely.