Chocolate Chip Cookies with Nutella, Brown Butter and Sea Salt

INGREDIENTS

Chocolate hazelnut spread (such as Nutella), about ½

1 cup

unsalted butter

2 1/4 cups

all-purpose flour

1 1/4 tsp

baking soda

1/2

tsp. coarse sea salt, plus more sprinkling

1 cup

light brown sugar

1/2 cup

granulated sugar

large egg plus 1 egg yolk

2 1/2 tsp

vanilla extract

1 tbsp

greek yogurt or sour cream

1 cup

semisweet chocolate chips

3/4 cup

dark chocolate chips