Baked Apple Pancake

Name: Baked Apple Pancake
Ingredients: 4 large eggs; 1 cup whole milk; 3 Tbsp. granulated sugar; 1 tsp. vanilla extract; ½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt; ¼ tsp. ground cinnamon; ⅔ cup (84 g) all-purpose flour; 4 Tbsp. unsalted butter; 2 Golden Delicious apples (about 12 oz.), peeled, cored, thinly sliced; 3 Tbsp. (packed) light brown sugar; Powdered sugar (for serving; optional)