Step 1

Heat oven to 425F.

Step 2

In a large bowl, whisk together the flour, baking powder, sugar, and sea salt. Set aside.

Step 3

In another bowl, whisk together the eggs, milk, melted and cooled butter and either of the optional ingredients (the vanilla or the lemon zest).

Step 4

Pour the wet ingredients into the center of the dry ingredients and then plop in all but a handful of the blueberries.

Step 5

Fold all together as evenly as you can. Work quickly and be thorough, but also be gentle. No stirring--just folding. It's a tall order, but you can do it. The batter will be very thick and scoopable, not pourable.

Step 6

Scoop batter by 1/2 cups into 12 jumbo muffin cups lined with parchment muffin tin liners

Step 7

Press a few blueberries into the top of each muffin and then sprinkle with 1/2 teaspoon of coarse sugar.

Step 8

Turn oven down to 400F, and bake until golden brown with an internal temperature of about 195F-200F, about 25 minutes. If the muffins get too brown before the insides are done, cover with foil.

Step 9

Cool in tins for 5 minutes and then remove to racks. Serve warm with a pat of butter.