Spread the flour on a microwave-safe plate and heat on high for 1 minute, stir, then heat in 30-second bursts until it reaches 160°F on an instant-read thermometer; this kills off any raw-flour bacteria. Let it cool completely, about 10 minutes.

In a large bowl, beat the butter and cream cheese with a hand mixer until smooth and fluffy with no visible lumps, about 2 minutes.

Add the brown sugar, vanilla and salt; beat until pale and completely smooth.

Add the cooled flour and mix on low speed just until no dry streaks remain.

Add the milk one tablespoon at a time, beating after each addition, until the dip is soft enough to scoop with a spoon but still holds its shape rather than pooling flat.

Fold in 1/2 cup of the chocolate chips by hand.

Cover and chill for 30 minutes so the flavors settle and the texture firms slightly.

Scrape into a serving bowl, scatter the remaining chocolate chips on top, and serve with pretzel sticks and graham crackers.