In a small saucepan, combine white chocolate, ½ cup cream, and butter. Cook over low heat, stirring frequently, until white chocolate is melted and mixture is smooth. Remove from heat, and let stand until mixture is room temperature.
In a large bowl, beat remaining 2 cups cream with a mixer at medium speed until stiff peaks form. Gently fold in cooled white chocolate mixture. Cover, and refrigerate for at least 4 hours or up to 2 days.
Recipe by Victoria at https://victoriamag.com/espresso-chocolate-trifles-with-chocolate-mousse-and-white-chocolate-truffle-recipe/