Step 1: Preheat the Oven and Prepare the Muffin Tin

Preheat your oven to 350°F (175°C). Line a 12-cup muffin tin with paper liners or lightly grease it with non-stick spray.

Step 2: Prepare the Dry Ingredients

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. This ensures even distribution of leavening agents, helping the muffins rise properly.

Step 3: Cream the Butter, Cream Cheese, and Sugar

In a large mixing bowl, use a hand mixer or stand mixer to beat the butter, cream cheese, and granulated sugar together until light and fluffy, about 2 minutes. This step incorporates air into the batter, leading to softer muffins.

Step 4: Add the Wet Ingredients

Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next. Add the vanilla extract, lemon juice, and lemon zest, mixing until combined.

Step 5: Combine the Wet and Dry Ingredients

Gradually add the dry ingredients to the wet mixture, alternating with the buttermilk. Start and end with the dry ingredients, mixing until just combined. Be careful not to overmix, as this can make the muffins dense.

Step 6: Make the Cream Cheese Filling

In a small bowl, mix the softened cream cheese, powdered sugar, and vanilla extract until smooth and creamy. Set aside.

Step 7: Fill the Muffin Cups

Spoon about 1 tablespoon of batter into each muffin cup. Add 1 teaspoon of the cream cheese filling to the center, then cover with another tablespoon of batter, ensuring the filling is enclosed.

Step 8: Bake the Muffins

Bake for 18-22 minutes, or until the tops are golden and a toothpick inserted into the muffin (not the cream cheese center) comes out clean.

Step 9: Cool and Glaze (Optional)

Let the muffins cool in the pan for 5 minutes, then transfer them to a wire rack to cool completely. If desired, whisk together the powdered sugar and lemon juice to make a glaze, then drizzle over the cooled muffins.