• Step 1: Preheat your oven to 325°F (165°C). Grease a 10-inch Bundt pan or a 9×5-inch loaf pan with butter or non-stick cooking spray, and lightly flour the pan.
• Step 2: In a large mixing bowl, cream the softened butter and sugar together until light and fluffy, about 3-5 minutes. Beat in the eggs one at a time, mixing well after each addition.
• Step 3: In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add the dry ingredients to the wet ingredients, mixing just until combined. Fold in the Key lime juice, zest, and vanilla extract until fully incorporated.
• Step 4: Pour the batter into the prepared Bundt or loaf pan, smoothing the top with a spatula. Bake for 60-70 minutes, or until a toothpick inserted into the center comes out clean.
• Step 5: Allow the cake to cool in the pan for 10-15 minutes, then invert it onto a wire rack to cool completely before serving.