Preheat oven to 350°F with a rack in the center. Line a sheet pan with foil (do not tuck over edges — you’ll use it later to shield the cake edges). Spray a 12-cup Bundt or tube pan with baking spray, rub with a paper towel to coat evenly, then spray lightly once more.

Combine the lemon juice and buttermilk in a small bowl. Stir and set aside.

In a large bowl, combine the sugar and lemon zest. Rub together with your fingers to release the oils from the zest.

Add 3 eggs and whisk vigorously for 1 full minute (set a timer). Add the remaining 3 eggs, one at a time, whisking 30 seconds after each addition.

Slowly stream in the olive oil while whisking until fully incorporated.

Add the baking powder, salt, and vanilla; whisk until combined.

Whisk in the almond flour. Add about ⅓ of the buttermilk mixture and whisk until incorporated. Add about 1 ½ cups of the flour and whisk just until combined. Repeat with another ⅓ of the buttermilk mixture and whisk briefly. Add the remaining flour and the final portion of the buttermilk mixture. Stir just until smooth and lump-free (do not overmix).

Pour batter into prepared pan. Bake for 25 minutes, then gently pull the foil up around the edges of the pan to prevent over-browning. Continue baking for a total of 45–55 minutes, or until a toothpick inserted in the center comes out clean or an instant-read thermometer registers 200–210°F.

Cool in the pan for 15 minutes, then invert onto a cooling rack set over parchment or foil.

While the cake cools slightly, prepare the glaze: Combine the sugar and lemon juice in a medium microwave-safe bowl (mixture will bubble). Microwave on high for 1 minute. Stir and microwave for another minute until the sugar is fully dissolved and the mixture is clear.

Slowly brush warm glaze over the cake, covering the top, sides, and center. Allow the glaze to soak in before adding more. Let cool completely before slicing.