Gluten-Free Pistachio Truffle Cookies

In a small saucepan, heat cream and brown rice syrup over medium heat until it just begins to simmer. Immediately remove the pot from heat and add chocolate. Let stand for 3 minutes, then stir until chocolate is melted and smooth. Add cognac and stir to combine. Transfer truffle filling to a medium bowl and let stand at room temperature until the texture thickens and resembles peanut butter, whisking occasionally, about 45 minutes.