In a medium saucepan melt the butter over medium high heat. Lower the heat and simmer for about 5 minutes until the butter turns a deep amber color and has a nutty smell. Stir occasionally, making sure the butter does not burn. Pour the butter into a bowl through a fine mesh strainer to remove any dark particles. Set the butter aside and wipe out the saucepan.

Pour the heavy cream, milk, sugar and brown sugar into the saucepan and bring the mixture to a simmer. Simmer for a few minutes until the sugar has dissolved.

Whisk the egg yolks in a small bowl until well beaten. Add 1 cup of the hot cream mixture to the egg yolks, whisking constantly. Continue to whisk and slowly pour the cream and yolks back into the pan. Simmer the mixture for about 5 minutes until it thickens and coats the back of a spoon. Remove the pan from the heat and whisk in the brown butter and dark rum.

Transfer the mixture to a bowl or container and chill for at least 4 hours.

While the mixture is chilling, heat a small skillet over medium-high heat. Add the almonds and tir or toss until toasted and lightly browned. Let the nuts cool.

Serve the ice cream immediately, soft serve style, or transfer it to a container and freeze for at least 4 hours for a harder, scoopable texture.