Preheat oven to 350° F.
Heat sugar in small, heavy-duty saucepan over medium-low heat, stirring constantly, for 3 to 4 minutes or until dissolved and caramel-colored. Pour onto bottom of 9-inch-round cake pan; quickly swirl around bottom to coat.
Place sweetened condensed milk and chopped strawberries or jam in blender; cover. Blend until smooth.
Combine strawberry mixture and eggs in large bowl; whisk until well combined. Add evaporated milk; mix well. Pour into prepared pan; cover lightly with foil. Place pan in large roasting pan; fill roasting pan with warm water to about 1-inch depth.
Bake for 1 hour and 15 minutes (if using regular La Lechera, bake for 50 to 60 minutes) or until knife inserted near center comes out clean. Remove flan from water. Cool on wire rack. Refrigerate for 4 hours or overnight.
To serve, run small spatula around edge of pan. Invert serving plate over pan. Turn over; shake gently to release. Garnish with strawberry slices if desired.