Adjust rack to upper middle position and preheat oven to 260°C. Whisk flour, 1 tablespoon sugar, and salt in medium bowl to combine. Whisk in milk, yogurt, eggs, and vanilla until just combined; set batter aside.
Stir remaining 4 tablespoons sugar with cinnamon in a small bowl. Heat butter in 10-inch non-stick oven-safe skillet over medium heat until melted. Increase heat to medium high and add apples and cinnamon-sugar to pan. Cook, stirring frequently, until apples have softened and are beginning to caramelize, 6 to 8 minutes.
Remove from heat, pour batter over apples and immediately place pan in oven. Reduce heat to 220°C and bake until pancake is puffed, just set in center, and golden around the edges, about 15 minutes.
Cool pan on wire rack for about 15 minutes, then carefully invert pancake onto serving plate. Dust with powdered sugar and serve.
