Preheat the oven to 450 degrees. In an ovenproof skillet just large enough to hold the strawberries in one layer, melt the butter in the preheating oven, 2 to 3 minutes. Watch carefully so that the butter does not burn. Remove pan from oven and stir in 2 tablespoons of the sugar. The mixture will be grainy. Add the berries, tossing to coat with the butter and sugar. Spread in a single layer. Roast, stirring and turning once or twice, until the berries just begin to soften, about 5 minutes. Gently roll the roasted berries in the pan syrup to coat, then let them cool for about 5 minutes in the skillet.
While the berries are roasting, whip the cream with the creme de menthe and remaining 1 tablespoon of sugar just until soft peaks form. Divide the chantilly cream among 4 shallow dessert bowls. Arrange the lukewarm berries in the chantilly cream, pointed ends up. Using a teaspoon, dribble the red pan glaze over the mint cream. Garnish with mint sprigs. Serve immediately.