Add the yogurt, milk, eggs, and butter to a medium bowl. To make a Sheet Pan Pancake: Preheat oven to 400 degrees F.
Whisk to combine into a smooth mixture. Line a half sheet pan with parchment paper and grease the sides with nonstick spray.
Add the flour, sugar, baking powder, and salt. Whisk gently to combine. To make for a baby, omit the sugar and use plain nondairy milk.
To make this a Sheet Pan Pancake: Pour out batter and spread gently with a spatula. Add toppings if desired. Bake for 12-14 minutes or until lightly golden brown and just firm to the touch.
Heat a large nonstick skillet over medium heat. Melt butter and swirl to coat the pan. Spoon out ¼ cup batter per pancake. Cook for 3-4 minutes. Flip over and cook for an additional 3 minutes.
Serve warm with applesauce, other fruit puree, maple syrup, and/or nut or seed butter as you like.
P.S. Store for up to 3-5 days in the fridge in an airtight container. Or freeze between layers of parchment paper in a freezer bag.