Prepare apricots by peeling, pitting, and slicing about 4 ripe apricots. Combine apricot slices with 1/4 cup of brown sugar and lemon juice, allowing to sit for 1 hour.

Make custard base by whisking together 4 egg yolks, 3/4 cup brown sugar, and 1 teaspoon vanilla until smooth. Heat 2 cups whole milk and 1 cup heavy cream in a saucepan until steaming, then gradually pour into the egg mixture while whisking.

Return the mixture to the saucepan and cook on low heat, stirring continuously for 5 to 7 minutes until thickened.

Strain the custard through a fine-mesh sieve into a bowl and stir in apricot juice. Cool to room temperature, then refrigerate for at least 2 hours or overnight.

Churn the custard in an ice cream maker for about 20 minutes, folding in the reserved apricot pieces in the last minute.

Transfer churned ice cream into an airtight container, smoothing the top, and freeze overnight.