This actually was a mistake on my part when I was going to make raspberry jam and found out that I didn't have enough raspberries to make it. I'm almost glad that I didn't though because then I wouldn't have made this great recipe.
You will also need 6 (12 ounces) jelly or jam jars, boiled or washed in HOT soapy water, then rinsed in HOT water Smash the raspberries and strawberries and place them in a large sauce pot with the water.
Bring to a simmer over medium-high heat then add the sugars.
Turn heat to high and bring to a rolling boil, stirring often.
Quickly stir in the pectin and let boil for 1 minute, stirring constantly.
Remove from the heat and ladle into the jars to about 1/2-inch from the top.
Place the lids on tight and turn the jars upside-down for 15 minutes then turn them right side up.
The jam will last for about 6 months in a cool, dark pantry and about 1 year in the refrigerator.