Bake and Slice Chocolate Swirls

INGREDIENTS

1 cup

semi-sweet chocolate chips

1/2 cup

sweetened condensed milk

1 tbsp

shortening

3/4 cup

butter, at room temperature

1/2 tsp

salt

1 tsp

vanilla extract

3/4 cup

brown sugar, packed

2 cups

all-purpose flour, measured then sifted

milk

3/4 cup

walnuts or almonds, chopped (optional)