Preheat your oven to 400°F (200°C). Hull and slice the strawberries and toss them with 4 tbsp of sugar, 1.5 tbsp of lemon juice, and 1/8 tsp of ground cinnamon.

Spread them evenly on a baking sheet and roast for 35-40 minutes, or until the strawberries darken and become syrupy. Stir in 2 tsp of vanilla after removing them from the oven. Let cool.

In a medium saucepan, whisk together the egg yolks, 3.5 oz of sugar, and 1/4 tsp of salt. Carefully heat over medium-low heat while stirring continuously until the mixture thickens and reaches 170°F (77°C), about 10-12 minutes.

Remove from heat and stir in 1 tbsp of vanilla extract, the milk, and 2 cups of cream.

Take half of the cooled roasted strawberries and use an immersion blender or a food processor to puree them until smooth. For a finer texture, strain the mixture to remove seeds if desired.

Gently fold the strawberry puree into the custard mixture. Cover and refrigerate overnight, or at least 4 hours, to let the flavors meld and the mixture cool completely.

Pour the chilled custard mixture into your ice cream maker and churn according to the manufacturer's instructions, usually about 20-25 minutes.

In an airtight container, layer the churned ice cream with the remaining roasted strawberries and sponge cake cubes. Start with ice cream, then alternating strawberries and sponge cake, ending with ice cream on top.

Freeze the container for at least 4 hours, or until solid. Serve with additional sponge cake and strawberries, if desired.