Prepare the Batter – Whisk flour, sugar, baking powder, baking soda, and salt. In another bowl, mix espresso, milk, butter, egg, and vanilla.
Combine Wet & Dry – Gently fold wet ingredients into the dry mixture. Stir until combined but don’t overmix—unless you like dense muffins.
Make the Cheesecake Swirl – Beat cream cheese, sugar, egg yolk, and vanilla until smooth and slightly dangerous-looking.
Fill the Muffin Cups – Spoon batter into a greased muffin tin, filling each cup about ¾ full.
Swirl in the Cheesecake – Drop a teaspoon of cheesecake mixture into each muffin, then swirl with a skewer or spoon.
Bake to Perfection – Bake at 350°F (175°C) for 18 minutes, or until a toothpick comes out with just a few moist crumbs.
Cool & Enjoy – Let them cool before eating—if you can wait that long.