Raspberry Custard Cake

This is an old slow cooker recipe I got from Woman's Day magazine I think?

Ingredients:

1 cup granulated sugar, divided

2 Tbsp butter, softened

4 eggs, separated

grated zest and juice of 1 lemon

pinch of salt

1/4 cup all purpose flour

1 cup milk

1 1/2 cups raspberries, thawed if frozen

1-2 Tbsp confectioners sugar

Directions:

1. In a bowl, beat 3/4 cup granulated sugar with butter until light and fluffy. Beat in egg yolks until incorporated.  Stir in lemon zest and juice. Add salt, then four and mix until blended.  Gradually add milk, beating to make a smooth batter.

2. In a separate bowl, with clean beaters, beat egg whiles until soft peaks form.  Add remaining 1/4 cup sugar and beat until stiff peaks form.  Fold into lemon mixture, then fold in raspberries.

3.  Pour mixture into a 6-cup lightly greased baking or souffle dish.  Cover with foil and tie tightly with a string.  Place dish in large (minimum 5-qt) oval slow cooker stoneware and add boiling water to come 1 in. up on the sides.  Cover and cook on High for 3 hours, until the cake springs back when touched lightly in the center.  Dust lightly with confectioners sugar and serve.