Most French-style macaroons are made with almonds, but these chocolate ganache sandwich cookies shine with peanuts.
For best results, bake these French-style macaroons on cooking parchment. They're best eaten the day they're filled; however, you can make both cookies and filling up to 3 days ahead. Stack cookies carefully in an airtight container and store at room temperature; cover ganache airtight and refrigerate. Melt ganache over hot water and cool before filling cookies.