Preheat your oven to 325 degrees Fahrenheit (163 degrees Celsius). Make sure your vegan butter is at room temperature. Cream the vegan butter and sugar together either with a stand mixer, or with a wooden spoon in a bowl.

Add the yogurt, vanilla extract, salt, lemon juice, and lemon zest, and continue to mix until well combined.

Add the flour with the baking powder on top of it, and stir together until smooth. If using a stand mixer, I recommend using the paddle attachment.

Cut a piece of parchment to fit into a 9-inch loaf pan, covering the bottom and the two long sides.  Leave the short ends uncovered by the paper to make to prevent buckling of the paper in the corners.  Bush the entire inside of the paper-lined pan with neutral-tasting oil (canola, safflower, melted vegan butter, or melted refined coconut oil).

Spoon the batter into the pan, and even out the top surface with a rubber spatula, or metal offset spatula.

Bake the loaf for 60-75 minutes at 325 degrees Fahrenheit (163 degrees Celsius. You will know it is done when the surface is lightly golden brown, the edges are just barely starting to pull away from the pan, and a toothpick can be inserted and removed from the center without being coated in wet batter.

While the loaf bakes, mix up the frosting.  Cream together the vegan cream cheese and elderflower liqueur in a stand mixer fitted with a whisk attachment, or by hand using a whisk and bowl. Add the powdered sugar and continue to whisk rapidly until completely smooth.

Cool the loaf in the pan for 30 minutes. Use a sharp knife to trace around the full perimeter of the pan to ensure the cake is not stuck anywhere.   

To remove the pound cake without damaging it, place a pan or plate larger than the size of the loaf over the top. Holding the loaf pan and the plate, quickly flip them upside-down together. Place them onto a flat surface and lift up the loaf pan to release the pound cake.  Place a wire cooling rack on top of the pound cake and flip the plate, pound cake and wire rack nightside up again.   Allow the pound cake to finish cooling for 10-15 minutes on the wire rack.

While the pound cake cools, spread the elderflower frosting onto the top of it, using an offset spatula or butter knife.