How to Make It
Preheat the oven to 350°. Butter one 9-by-5-inch loaf pan. Combine the yogurt, chia seeds and zest in a small bowl and set aside. In a medium bowl, whisk together the flour, baking soda and salt.
With an electric mixer on high speed, beat the butter and granulated sugar in a large mixing bowl until light and fluffy, about 4 minutes. Stir in the vanilla extract and then add the eggs in one at a time, beating well with each addition. Reduce the speed to low; beat in the dry ingredients in 3 batches, alternating with 2 batches of the chia yogurt mixture.
Pour batter evenly into prepared pan and smooth the top with an offset spatula. Bake until a cake tester comes out clean, about 35 to 40 minutes. If the top begins to brown towards the final minutes in baking, tent the cake loosely with a strip of tin foil.
In a medium saucepan, combine the granulated sugar and the water and bring to a boil, stirring to dissolve the sugar. Add the clementine slices and simmer gently over medium-low heat for about 8 minutes until slices are moderately opaque, lightly stirring the slices every other minute or so. Turn off the heat and transfer slices to a sheet of waxed paper. Stir in the citrus juice into the syrup to taste.
Once the cake is out of the oven, use a wooden skewer to poke a few holes in the top of the loaf. Slowly pour the syrup in 2 or 3 additions over the surface of the pound cake, reserving some syrup to also brush the sides with as well. Transfer cake to a wire rack to cool completely, about 1 hour. Turn cake onto rack and line it underneath with a sheet of parchment paper.
Combine the confectioners' sugar and lemon juice together, adjusting with more lemon juice if consistency is too thick. Pour the glaze over the cake letting it drip down the sides. Let it set, and garnish with the candied clementine slices and a sprinkling of chia seeds.