Method
Cream the butter and sugar in an electric stand mixer on medium speed until well-combined, about 1 minute. Add the egg yolk and vanilla extract and mix on low speed for another 30 seconds. Add the flour, baking soda, and salt and mix on medium speed until a dough forms.
Wrap the dough in plastic wrap or aluminum foil and chill for 30 to 60 minutes.
Preheat the oven to 350. Line a baking sheet with parchment paper. Roll the chill dough into balls about 1 1/4 inches in diameter and place them a few inches apart on the baking sheet. Lightly press down on each ball with your thumb to make a small well in the center of the cookie, being careful to not press too hard. Add about 1/2 tsp of Sweet Mango Chutney to each well.
Bake for 15 minutes or until slightly firm. Cool on the baking sheet for a few minutes, then transfer to a cooling rack.