Preheat the oven to 350 degrees F and line a 9” x 5” loaf pan with parchment paper.
Beat the eggs, vanilla extract, melted butter, and lemon juice together in a mixing bowl. In a separate bowl, stir together the coconut flour, sugar-free sweetener, baking soda and sea salt until well-combined.
Stir the dry mixture into the bowl with the wet mixture and beat until well combined. Stir in the lemon zest and poppy seeds. The batter will become very thick and crumbly.
Transfer batter to the parchment-lined loaf pan and use your hands or a rubber spatula to pat the batter down into an even layer.
Bake on the center rack of the preheated oven 50 to 55 minutes, until bread is golden-brown and tests clean when poked in the center with a toothpick.
If making the glaze, heat the coconut butter in the microwave for 20 second intervals, stirring well between each interval, until melted and creamy. Stir in the sugar-free confectioners sugar.
Allow bread to cool at least 20 minutes before adding the glaze, slicing and serving.