Preheat the oven to 350°F. Line two baking sheets with parchment paper. Adjust oven rack to middle and upper positions and in a medium bowl, combine flour, baking powder, baking soda, and salt. Make a well in the center whisk oil, eggs and silan. Add lemon zest and vanilla extract. Combine with dry ingredients until just mixed. Stir in almonds. Divide dough into four equal parts. Shape each part into 3-inch wide log. Bake until golden, about 20 minutes. Take cookies out of oven and reduce heat to 300°F. When cool enough to handle, cut each log on the bias to form 1-inch wide cookies. Place cookies cut side down on baking sheet and bake until toasted, 15 minutes more, flip and cook another 10 minutes. Let cool for 5 minutes then transfer for a wire rack to finish cooling. Cookies will keep, stored in an airtight container, for up to 1 week or for a few months in the freezer.