Prepare the Oven: Preheat your oven to 350°F (175°C). Line a 9×5-inch loaf pan with parchment paper or grease it lightly.

Make the Strawberry Swirl: In a small saucepan, combine the chopped strawberries, erythritol, and lemon juice. Cook over medium heat, stirring occasionally, until the strawberries break down and the mixture thickens, about 10-12 minutes. Let cool.

Mix the Batter: In a large bowl, whisk together the almond flour, coconut flour, erythritol, baking powder, and salt. In another bowl, combine the melted butter, eggs, almond milk, and vanilla extract. Add the wet ingredients to the dry ingredients and mix until just combined.

Add Strawberry Swirl: Pour half of the batter into the prepared loaf pan. Spoon half of the strawberry mixture over the batter. Use a knife or skewer to gently swirl the strawberry mixture into the batter. Repeat with the remaining batter and strawberry mixture.

Bake the Loaf: Bake in the preheated oven for 40-50 minutes, or until a toothpick inserted into the center comes out clean. The top should be golden brown.

Cool and Serve: Allow the loaf to cool in the pan for 10 minutes before transferring it to a wire rack to cool completely. Slice and serve.