Step 1: Prepare the Strawberry Swirl

1. In a small saucepan, combine the strawberries, sugar, and lemon juice over medium heat.
2. Stir occasionally and cook for about 5-7 minutes, until the strawberries release their juices and become soft.
3. If the mixture seems too runny, add cornstarch and cook for another 2 minutes until it thickens.
4. Use a blender or food processor to puree the mixture until smooth. Let it cool completely.

Step 2: Make the Cake Batter

1. Preheat your oven to 325°F (160°C). Grease and flour a 10-inch bundt pan or tube pan.
2. In a large bowl, beat the butter and cream cheese together until smooth and creamy.
3. Gradually add the sugar, beating well after each addition until the mixture is light and fluffy.
4. Add the eggs, one at a time, beating well after each addition.
5. Mix in the vanilla extract.
6. In a separate bowl, whisk together the flour, baking powder, and salt.
7. Gradually add the dry ingredients to the wet mixture, mixing just until combined. Do not overmix.

Step 3: Layer the Batter and Strawberry Swirl

1. Pour half of the cake batter into the prepared pan, spreading it evenly.
2. Spoon half of the strawberry puree over the batter and use a knife to gently swirl it.
3. Pour the remaining batter on top and repeat the swirl process with the rest of the strawberry puree.

Step 4: Bake the Pound Cake

1. Place the cake in the preheated oven and bake for 1 hour and 15 minutes to 1 hour and 30 minutes, or until a toothpick inserted into the center comes out clean.
2. If the top starts browning too quickly, cover it loosely with aluminum foil.

Step 5: Cool and Serve

1. Remove the cake from the oven and let it cool in the pan for 10-15 minutes.
2. Carefully invert the cake onto a wire rack and let it cool completely before slicing.