Step 1: Preheat your oven to 425°F (220°C). Place 1 teaspoon of unsalted butter in each cup of a standard 6-cup muffin tin, or if using ramekins, distribute the ¼ cup melted butter among them. Place the muffin tin/ramekins in the preheating oven to melt the butter and get them very hot.
Step 2: In a medium bowl, whisk together the all-purpose flour, kosher salt, and baking powder until well combined.
Step 3: In a separate larger bowl, whisk the large eggs vigorously for about 1 minute until they are foamy. Add the milk and vanilla extract to the eggs and whisk until just combined.
Step 4: Gradually add the dry ingredients to the wet ingredients, whisking until the batter is smooth and free of lumps. Be careful not to overmix.
Step 5: Carefully remove the hot muffin tin/ramekins from the oven. Pour the batter evenly into the hot, buttered cups, filling each approximately two-thirds full.
Step 6: Immediately return the muffin tin/ramekins to the preheated oven. Bake for 15-20 minutes, or until the mini pancakes are dramatically puffed up, golden brown, and slightly crispy around the edges.
Step 7: Remove from the oven and serve immediately. Dust generously with powdered sugar and top with maple syrup or fresh fruit as desired.