1. Preheat oven to 350°. Beat butter and sugars at medium speed with a heavy-duty electric stand mixer until creamy. Add eggs, 1 at a time, beating just until blended after each addition. Add vanilla, beating until blended.
2. Combine flour and next 2 ingredients in a small bowl; gradually add to butter mixture, beating at low speed just until blended. Stir in morsels just until combined. Drop dough by level spoonfuls onto parchment paper-lined baking sheets, using a small cookie scoop (about 1 1/8 inches).
3. Bake at 350° for 12 minutes or until golden brown. Remove from baking sheets to wire racks, and cool completely (about 30 minutes).
4. Spread Bourbon Ganache on flat side of half of cookies (about 1 Tbsp. per cookie); top with remaining cookies. Cover and chill cookies 2 hours or until ganache is firm.