Preheat your oven to 180°C (350°F) and grease your muffin tin or line with paper liners.
In a large bowl, combine the rolled oats, all-purpose flour, brown sugar, and baking powder. Mix until evenly distributed; this creates the dry base for your muffins.
1 1/2 cups rolled oats, 1 cup all-purpose flour, 1/2 cup brown sugar, 1 teaspoon baking powder
In a separate bowl, whisk together the eggs, melted butter or coconut oil, buttermilk, and vanilla extract until the mixture is smooth and slightly frothy, releasing a pleasant aroma.
2 eggs eggs, 1/2 cup melted butter or coconut oil, 1 cup buttermilk, 1 teaspoon vanilla extract
Pour the wet mixture into the dry ingredients, then gently fold with a spatula or spoon until just combined. Be careful not to overmix; the batter should be slightly lumpy but well incorporated.
If using, fold in chopped nuts or berries now, distributing them evenly throughout the batter for bursts of flavor.
1/2 cup chopped nuts or berries
Spoon the batter into the prepared muffin cups, filling each about 3/4 full for a domed top. Tap the tin lightly on the counter to settle the batter and remove air bubbles.
Mix the oats and sugar for the topping, then sprinkle generously over each muffin to develop that irresistible crispy crust.
2 tablespoons oats for topping, 1 tablespoon sugar for topping
Bake in the preheated oven for 20–25 minutes, until the tops are golden brown and a toothpick inserted into the center comes out clean. The smell of toasted oats will fill your kitchen.
Remove the muffins from the oven and let them cool in the tin for about 5 minutes, allowing the crust to set.
Transfer the muffins to a wire rack and allow them to cool completely for a moist, tender crumb with a crispy, toasted top.
Serve these warm or at room temperature, with a pat of butter or a spread of jam if desired. Enjoy the delightful crunch and moist interior with every bite!
