Line a baking sheet with parchment paper.
In a large bowl, whisk together flour, granulated sugar, baking powder, and salt. Using your hands or a pastry blender, cut in cold butter until mixture resembles coarse crumbs; stir in butterscotch chips.
In a liquid-measuring cup, combine 1 cup (240 grams) cold cream and butterscotch vanilla extract; add cream mixture to fl our mixture, and fold just until moistened. Turn out dough onto a lightly floured surface, and knead just until dough comes together, 7 to 8 times. Pat dough into a 7-inch circle (about 1 inch thick); using a sharp knife or bench scraper, cut into 8 wedges. Place wedges on prepared pan. Freeze until firm, 10 to 15 minutes.
Preheat oven to 400°F (200°C).
Brush 2 tablespoons (30 grams) cold cream onto scones.
Bake until golden brown, 15 to 20 minutes. Let cool on pan for 5 minutes. Remove from pan, and let cool on a wire rack for 10 minutes.
In a small bowl, whisk together confectioners’ sugar, vanilla paste, and remaining 2 to 3 tablespoons (30 to 45 grams) cold cream until smooth and pourable; drizzle onto warm scones. Serve warm.