Preheat your oven to 375°F (190°C).
Peel, core, and dice the Granny Smith apple into small bite-sized pieces.
In a small bowl, toss the diced apple pieces with 0.25 tsp of the ground cinnamon and 0.25 tbsp of the maple syrup.
Place the apples into a small oven-safe ramekin and bake for 15 minutes until they are tender and juicy.
While the apples bake, combine the old fashioned oats, chopped walnuts, coconut oil, the remaining 0.25 tsp of ground cinnamon, ground ginger, and sea salt in a small skillet over medium heat.
Toast the oat mixture for 4 minutes, stirring frequently until the oats are golden and the walnuts are fragrant.
In a separate bowl, whisk the non-fat Greek yogurt with the vanilla extract and the remaining 0.25 tbsp of maple syrup until smooth.
Spoon the creamy yogurt into a serving bowl and layer the warm baked apples directly on top.
Finish the dish by sprinkling the crunchy toasted oat crumble over the apples and serve immediately.