Step 1: Prepare the Cake Batter

1. Preheat your oven to 350°F (175°C). Grease and flour a 9×5-inch loaf pan or a bundt pan to prevent sticking.
2. In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
3. In a large mixing bowl, cream the butter and sugar together using a hand mixer or stand mixer on medium speed until light and fluffy (about 3-5 minutes).
4. Add eggs one at a time, mixing well after each addition. Add the lemon juice, lemon zest, and vanilla extract, mixing until combined.
5. Gradually alternate adding the flour mixture and buttermilk, starting and ending with the flour mixture. Beat each addition until just combined, careful not to overmix.

Step 2: Bake the Cake

1. Pour the batter into the prepared loaf or bundt pan, spreading it evenly with a spatula.
2. Bake in the preheated oven for 55-65 minutes, or until a toothpick inserted into the center comes out clean. If the top browns too quickly, cover loosely with aluminum foil during the last 10-15 minutes of baking.
3. Remove from the oven and let the cake cool in the pan for 15 minutes. Then, transfer the cake to a wire rack to cool completely.

Step 3: Prepare the Lavender Glaze

1. In a small mixing bowl, whisk together powdered sugar, milk or cream, ground lavender flowers, and lemon juice until smooth. If the glaze is too thick, add a little more milk; if it’s too thin, add more powdered sugar.
2. Pour the lavender glaze over the cooled cake, letting it drip down the sides for a rustic look.

Step 4: Add the Toppings

1. While the glaze is still slightly wet, sprinkle toasted almond slices over the cake.
2. Garnish with a touch of fresh lemon zest and optional fresh lavender sprigs for added aroma and beauty.

Step 5: Serve and Enjoy

1. Slice and serve the cake, enjoying the combination of lemony, floral, and nutty flavors.