In a large sauté pan, cook beef over medium-high heat until browned and crumbly. Drain beef. Add 1 cup broth, onion, carrot, tomatoes, peas, corn, garlic, salt, pepper, rosemary, thyme, and sage; bring to a simmer. Reduce heat to low, and simmer for 10 minutes. Remove from heat.
Stir red wine into beef mixture. (If beef mixture looks too dry, add remaining ¼ cup stock, stirring well.) Transfer mixture to a large heatproof bowl. Let cool completely.
Preheat oven to broil.
Place Herbed Russet Potatoes on 2 rimmed baking sheets. Spoon 1 to 1½ teaspoons beef mixture into wells of Herbed Russet Potatoes.
Place Whipped Potatoes in a large piping bag fitted with a small star tip (Ateco #822). Pipe a small rosette on each filled potato.
Broil until rosettes are crisp, approximately 5 minutes. Garnish with thyme, if desired.
Recipe by TeaTime Magazine at https://teatimemagazine.com/shepherds-pies/