Preheat your oven to 350°F (175°C). Line a standard loaf pan with parchment paper.
In a food processor, combine cream cheese, butter, and sweetener. Pulse until smooth. Incorporate eggs, lemon juice, almond flour, coconut flour, baking powder, and lemon zest, pulsing until the mixture is well combined.
Transfer the thick batter to the prepared loaf pan.
Bake for 60-70 minutes, or until the center is firm to the touch and edges are a deep golden brown. If the cake is browning too quickly, cover with foil at the 45-minute mark.
Allow the cake to cool in the pan for 10 minutes, then use a knife to loosen the edges before lifting it out by the parchment paper. Let it cool completely before glazing.
For the glaze, mix all ingredients, adjusting water as needed to achieve the desired consistency. Spread over the cooled cake.