Serving ideas: fresh berries; honey and/or pure maple syrup; jam; whipped cream; Greek yogurt
Place a rack in the center of your oven (make sure there isn't another rack close above it, or the pancake will rise and hit the rack as it bakes). Preheat the oven to 450 degrees F.
Place the butter in a 9, 10, or 11-inch ovenproof skillet. A few minutes before you are ready to bake the pancakes, place the skillet in the oven as it preheats so that the skillet gets hot and the butter melts. You want this skillet to get nice and hot and the butter to melt, but don’t let the butter sputter too much or burn.
In a large bowl, briskly whisk together the eggs, milk, honey, vanilla, and lemon zest.
Add the whole wheat and all-purpose flours and salt. Very gently whisk just until the flour disappears. The batter will look lumpy at this point, which is just fine.
Remove the skillet from the oven and swirl to coat the pan with the melted butter. Working quickly, pour in the batter.
Return the skillet to the oven and bake the pancake for 9 to 11 minutes, unit it is puffy, dark golden brown at the topmost edges, and the center is set. It will be super puffy when you first pull it out, then settle as it cools. Dust with powdered sugar. Slice and serve warm with desired toppings.
For a smaller pancake, reduce the batter by 3/4 and bake in an 8x11-inch baking dish or reduce by half and bake in an 8x8 inch pan. Watch the baking time carefully, as it may need to be reduced. This oven pancake tastes best the day that it is made. It can be reheated, but the texture will not be as soft and delicate.
TO STORE: Cover and refrigerate leftovers for up to 4 days.
TO REHEAT: Gently rewarm the pancake in the oven at 350 degrees F or in the microwave.
TO FREEZE: Freeze leftovers without toppings in an airtight, freezer-safe storage container for up to 3 months. Thaw overnight in the refrigerator before reheating.