- Preheat oven to 350°F.
- Stir rhubarb, sugar and ginger (if using) in a medium bowl. Divide the mixture evenly among six 8-ounce ramekins.
- Place the ramekins on a baking sheet and cover tightly with foil.
- Bake until the rhubarb is softened, 25 to 30 minutes.
- Remove from the oven and remove the foil.
- Carefully tuck strawberries between the chunks of rhubarb. (Do not stir or the rhubarb will break apart.)
- Beat egg whites and cream of tartar in a large bowl with an electric mixer on medium until soft peaks form.
- Gradually add sugar and continue mixing until the egg whites are glossy and hold peaks.
- Spoon beaten egg whites over each portion of fruit.
- Use a thin spatula to spread the meringue into decorative peaks.
- Return the ramekins to the oven and bake until the meringue is lightly browned, about 10 minutes. Let cool for at least 10 minutes.
- Serve warm or at room temperature. Variation: This dish can be made in a deep-dish pie pan instead of individual ramekins; the recipe and timing are the same.