Start by preheating your oven to 350°F (175°C). This ensures a consistent bake. While the oven warms up, grease your bundt pan generously with butter or cooking spray and dust it lightly with flour. This will prevent any sticking and help your cake come out with a beautiful crust.

In a medium-sized bowl, whisk together the flour, baking soda, baking powder, salt, cinnamon, and nutmeg. This blend is crucial as it evenly distributes the leavening agents, ensuring your cake rises beautifully without any odd pockets of flavor. Set this mixture aside for now.

In a large mixing bowl, add the sugar and Greek yogurt. Using a whisk or an electric mixer, beat these together until smooth. The yogurt adds richness and moisture, creating a lovely texture. Next, mix in the applesauce, egg, oil, and vanilla extract. Stir until you achieve a homogenous mixture; don’t be afraid if it’s a little lumpy!

Gradually combine the wet and dry mixtures. Pour the dry ingredients into the bowl of wet ingredients and fold gently using a spatula until just combined. It's okay if there are a few lumps; over-mixing can lead to a dense cake.

Now it’s time for the best part: the walnuts! Fold in the chopped walnuts until evenly distributed throughout the batter. This adds a nice crunch and nutty flavor that complements the sweetness of the applesauce.

Carefully pour the batter into your prepared bundt pan, smoothing the top with your spatula. Give the pan a gentle tap on the counter to eliminate any air bubbles that may have formed.

Transfer the bundt pan to your preheated oven and bake for about 50-60 minutes. Keep an eye on it, and to check for doneness, insert a toothpick into the center. If it comes out clean or with a few crumbs, it’s ready to come out.

Once baked, remove the pan from the oven and let it cool on a wire rack for about 10-15 minutes. This cooling period is important to help the cake firm up. After that, carefully invert the bundt pan onto a serving plate. Allow the cake to cool completely before slicing. Trust me; the wait is worth it!