Preheat the oven to 350 degrees F. Generously oil an 8½ x 4¼-inch metal loaf pan.

To make the cake, put the coconut oil and sugar in a large bowl and beat with an electric mixer on medium speed until light and fluffy. Add the applesauce and lemon zest and beat on low speed until blended. Put the flour mix, quinoa flour, xanthan gum, baking powder, baking soda, and salt in a medium bowl and whisk to combine.

Put the water, lemon juice, and lemon extract in a small bowl or measuring cup and stir to combine. With the mixer on medium speed, beat the dry ingredients into the sugar mixture, alternating with the lemon water and beginning and ending with the dry ingredients. Mix until just combined. Beat ¼ cup of poppy seeds into the batter before spooning the batter into the oiled loaf pan. The batter will be thick and somewhat elastic.

Bake on the center rack of the oven for about 60 minutes, until the top is golden brown and a toothpick inserted in the center tests clean. Cool the cake in the pan on a rack for 5 minutes, then remove from pan and cool on the rack.

To make the glaze, put the sugar and lemon juice in a small saucepan. Bring to a boil over medium-high heat and boil for 1 minute. Remove from the heat and let cool. Put a sheet of waxed paper under the cake and rack. Drizzle the glaze over the cake while the glaze and cake are still a little warm.