Preheat oven to 400°F (200°C). Line baking sheets with parchment paper.
In the bowl of a stand mixer fitted with the paddle attachment, beat 1 cup (227 grams) butter and ½ cup (60 grams) confectioners’ sugar at low speed; slowly increase mixer speed to medium, beating until light and creamy, 3 to 4 minutes, stopping to scrape sides of bowl. Beat in 1 teaspoon (6 grams) vanilla bean paste.
In a medium bowl, whisk together flour and ½ teaspoon (1.5 grams) salt. With mixer on low speed, gradually add flour mixture to butter mixture, beating until a dough forms. Using a 1½-tablespoon spring-loaded scoop, scoop dough (about 24 grams), and roll into balls.
In a small bowl, stir together white sparking sugar and 1 tablespoon (12 grams) vanilla sugar. In another small bowl, stir together blue sparkling sugar and remaining 1 tablespoon (12 grams) vanilla sugar. Roll half of dough balls in each sugar mixture, and place 3 inches apart on prepared pans; leave rounded, or gently press into 2-inch disks for a flatter sandwich cookie.
Bake, one batch at a time, until edges are lightly golden, 8 to 10 minutes, rotating pan halfway through baking. Let cool on pan for 3 minutes. Remove from pan, and let cool completely on wire racks.
Clean bowl of stand mixer and paddle attachment. Using the paddle attachment, beat remaining ¾ cup (170 grams) butter and remaining ¼ teaspoon salt at medium speed until smooth, 2 to 3 minutes. Beat in honey and remaining 1 teaspoon (6 grams) vanilla bean paste. With mixer on low speed, gradually add remaining 2 cups (240 grams) confectioners’ sugar, beating until combined. Add cold cream; increase mixer speed to medium-high, and beat until light and fluffy, 1 to 2 minutes.
Spoon buttercream into a pastry bag fitted with a large round piping tip (Wilton 1A). Pipe buttercream onto flat side of half of cookies. Place remaining cookies, flat side down, on top of buttercream. Serve immediately.