2 heaping cups fresh raspberries, rinsed and drained
2 heaping cups fresh Marionberries, rinsed and drained
2 cups fresh blueberries, rinsed and drained
2 1/4 cups turbinado sugar (I use "Sugar in the Raw" brand)
2 cups granulated sugar
1/3 cup fresh lemon juice
Preheat oven to 450 F.
In a large bowl, combine the berries. Add the turbinado sugar, granulated sugar and lemon juice. With very large spoons or a rubber spatula, gently toss berries with sugar to evenly distribute sugar. Before juices begin to run, divide berry-sugar mixture between two 9-by-13-inch, glass baking dishes.
Bake in preheated oven for 15 minutes, stirring halfway through when mixture begins to bubble and foam around edges. Reduce oven temperature to 350 F, stir fruit again and continue baking for 20 minutes.
Remove baking dishes from oven and let stand until they have cooled slightly and fruit has stopped bubbling. Carefully scrape both dishes of jam into a bowl. Once in bowl, it is easier to ladle preserves into individual containers for storage in refrigerator or freezer.
For long-term storage at room temperature, have 5 half-pint canning jars washed and ready for filling when jam is done baking. After jam has been poured into a bowl, but while it is still hot, ladle into 1 clean and hot canning jar at a time, leaving 1/4 inch head space. Wipe jar rim with a clean, damp cloth. Attach lid. Fill and close remaining jars. Process in a boiling-water canner for 10 minutes (15 minutes at 1,000 to 3,000 feet; 20 minutes at 3,000 to 6,000 feet; 25 minutes above 6,000 feet). Makes about 5 half-pints.