Preheat your oven to 375°F (190°C) and grease a 24-cup mini muffin tin generously with cooking spray or butter.
In a large bowl, whisk together flour, sugar, baking powder, and salt. Make a well in the center.
In another bowl, whisk eggs until frothy. Add milk, melted butter, and vanilla, and whisk until well combined.
Pour the wet ingredients into the dry ingredients and fold together gently, being careful not to overmix.
Add any desired mix-ins, like chocolate chips, blueberries, or diced bananas.
Fill each muffin cup 2/3 full with batter. For sausage bites, place a piece of cooked sausage in the center before topping with more batter.
Bake for 10-12 minutes until golden and puffed. A toothpick inserted should come out clean.
Let cool for 2 minutes in the tin, then carefully remove and serve warm with maple syrup or powdered sugar.