Preheat grill on setting #4. Stir together mascarpone, milk, sugar and vanilla until well combined. Dollop the filling along the bottom third of each tortilla; sprinkle with strawberries. Fold in the sides and tightly roll up to enclose filling. Brush evenly with melted butter and sprinkle with sugar.
Grill for 3 to 5 minutes per side or until tortillas are golden and filling is warmed through. Cut in half and drizzle with chocolate sauce before serving (if using).
Tip: Sprinkle toasted shredded coconut over strawberries before enclosing filling if desired.