Prep the pan and oven: Preheat the oven to 350°F (175°C). Line a 9x5-inch loaf pan with parchment paper, letting the sides overhang for easy lifting.
Lightly grease the sides.
Mix dry ingredients: In a large bowl, whisk almond flour, sweetener, baking powder, baking soda, and salt until no lumps remain.
Add wet ingredients: Add eggs, almond milk, melted butter or oil, vanilla, lemon zest, and lemon juice. Whisk until just combined and smooth. The batter will be thick but spreadable.
Fill the pan: Scrape the batter into the prepared pan and smooth the top with a spatula.
Bake: Bake for 35–45 minutes, or until the top is golden and a toothpick comes out mostly clean with a few moist crumbs.
If browning too quickly, tent loosely with foil for the last 10 minutes.
Cool: Let the bread cool in the pan for 15 minutes, then lift it out using the parchment and transfer to a wire rack. Cool completely before glazing or slicing.
Glaze (optional): In a small bowl, whisk powdered sweetener with lemon juice. Add almond milk a splash at a time until you reach a pourable consistency.
Drizzle over the cooled loaf and let it set for 10–15 minutes.
Slice and serve: Cut into thick slices. Enjoy as-is or with a pat of butter.