Line a 12-cup muffin tin with paper liners. Lightly grease liners with nonstick spray.
In a large mixing bowl, use a hand mixer to cream the softened ½ cup butter and 1 cup granulated sugar until smooth and creamy, about 2 minutes.
Beat in 2 eggs until combined, about 20 to 30 seconds. Add 2 teaspoons baking powder, ½ teaspoon salt, 1 teaspoon vanilla extract, and any optional spices. Mix briefly.
Add 1 cup of flour and mix until just combined. Then add ½ cup milk (or buttermilk) and stir to combine. Scrape down the sides and bottom of the bowl, then add the remaining 1 cup of flour. Mix until just combined, being careful not to overmix.
If using, use a rubber spatula to gently fold in 1 cup of any add-ins such as chocolate chips, berries, or nuts.
Divide the batter evenly among the 12 muffin cups, filling each about ¾ full. Let the batter rest while preheating the oven.
Preheat the oven to 425°F (220°C).
Bake in the preheated oven for 7 minutes. Without opening the door, reduce the heat in the oven to 350°F (175°C) and bake for an additional 13-15 minutes. Watch the muffins closely as cooking times may vary depending on your oven.
Let muffins cool in the pan for 5 minutes before transferring to a wire rack to cool completely.
Video
[yeetvid]
Notes
Extracts: The vanilla extract can be replaced in the same amount with other flavors like almond extract, lemon extract, and orange extract. For cinnamon or pumpkin spice muffins, use 1/2 to 1 teaspoon total of ground cinnamon.For citrus flavors, use citrus extracts and add up to 2 tablespoons of orange or lemon zest. For chocolate muffins, add 1/2 cup cocoa powder with the sugar. For pistachio muffins, replace 1/4 cup of the sugar with a 3.4-ounce package of Instant Pistachio PuddingFor poppy seed muffins, add 3 tablespoons of poppy seeds.Add-ins should total up to 1 cup. Feel free to mix and match with the following options: chocolate chips (milk, semi-sweet, white, or mini), cinnamon chips, fresh or frozen berries. dried fruits like cranberries or raisins, chopped nuts (walnuts, pecans, almonds, pistachio, or macadamia).Streusel Topping: Stir together 1/2 cup brown sugar, 1/2 cup all-purpose flour, 1/4 teaspoon salt, and 1/4 teaspoon ground cinnamon (optional) in a medium-sized mixing bowl. Use a pastry blender to cut 4 tablespoons cold butter into the flour mixture until it resembles small pebbles or sand. Spoon on top of muffin batter just before baking. Other Toppings: Oats and brown sugar (1/4 cup of each) sprinkled on top, 1/4 to 1/3 cup of finely chopped nuts, sprinkle 1 teaspoon granulated sugar or sugar crystals, or decorate with thin slices of fruit.