A sure crowd pleaser that can be made ahead.
Preheat oven to 375°F. Line two baking sheets with parchment paper.
Place potatoes in large bowl and toss with olive oil and 1/2 teaspoon salt. Place half of potato slices in single layer on the prepared baking sheets. Bake for about 20 to 25 minutes, or until golden brown. Turn chips once during baking.
Remove trays from oven and season with salt & pepper. Cool slightly, transfer chips to container and repeat process with the second batch.
Store baked chips in an airtight container for up to one week.
Preheat grill to medium-high heat. Or heat a cast-iron or grill pan over medium-high heat.
Brush the onion slices generously with olive oil. Place the slices directly on the grill grate or pan. Cook until tender and charred, about 6 minutes on each side. Transfer to a plate to cool. Reserve several inner rings for garnish and finely chop remaining charred onion.
Combine the sour cream, mascarpone, mustard, chives, lemon juice and Worcestershire in a medium bowl. Fold in the chopped onions, then taste and season with salt and pepper. Add Tabasco sauce, if using. Cover and refrigerate until ready to use.
Place dip in serving bowl; garnish with chopped chives and reserved grilled onion. Serve with potato chips and/or crudités.
NOTE: Can be served right away but the flavors are more developed the next day. Can be stored in the refrigerator in an airtight container for up to three days.