In a small saucepan, cook milk and flour over medium heat, whisking constantly, until thickened and pudding-like and an instant-read thermometer registers 170°F (77°C), 4 to 5 minutes. Remove from heat, and whisk in extracts and salt. Pour into a small bowl; cover with a piece of plastic wrap, pressing wrap directly onto surface of mixture to prevent a skin from forming. Refrigerate until completely cool, about 1 hour.

In the bowl of a stand mixer fitted with the paddle attachment, beat Browned Butter at medium speed until creamy and smooth, about 2 minutes. With mixer on medium speed, gradually add sugar, and beat until smooth and fluffy, 6 to 7 minutes. Gradually add milk mixture, and beat until light and fluffy. (It should look like whipped cream.) Use immediately.