Prep the pan and oven: Heat your oven to 350°F (175°C). Line the loaf pan with parchment, letting it overhang for easy lifting. Lightly grease any exposed sides.

Mix dry ingredients: In a bowl, whisk the gluten-free flour, almond flour, baking powder, and salt until well combined. This helps prevent clumps and ensures even rise.

Flavor the sugar: In a large bowl, add sugar and lemon zest. Rub them together with your fingertips for 30–60 seconds until fragrant and slightly damp. This releases the lemon oils and boosts flavor.

Whisk in wet ingredients: Add eggs, yogurt, melted butter, oil, and vanilla to the lemon sugar. Whisk until smooth and glossy, about 30 seconds.

Combine batter: Add the dry ingredients to the wet. Stir with a spatula just until no dry streaks remain. The batter will be thick but scoopable; avoid overmixing to keep it tender.

Fill and bake: Scrape the batter into the prepared pan and smooth the top. Bake for 45–55 minutes, until the top is golden and a skewer inserted into the center comes out with a few moist crumbs, not wet batter. If it browns too quickly, tent loosely with foil.

Make the drizzle: While the cake bakes, stir together lemon juice and sugar until the sugar is mostly dissolved. No need to heat; a little graininess helps with that classic crunch.

Drizzle while warm: Let the cake cool in the pan for 10 minutes. Poke holes all over the top with a skewer. Slowly spoon the lemon drizzle over the warm cake, letting it soak in. Use it all.

Cool completely: Lift the cake out with the parchment and let it cool on a rack. If using the optional icing, whisk powdered sugar with lemon juice to a pourable glaze and drizzle over the fully cooled cake.

Slice and serve: Use a sharp knife for clean slices. Wipe the blade between cuts if the glaze is sticky.