Strawberry-raspberry jam with stevia

Based on this recipe

4 cups of thawed, crushed strawberries and raspberries (I used a bit more raspberry than strawberry because that was what I had. Measured after thawing and crushing – you should thaw about 2L of unsweetened berries to get this much)
1 cup pure cranberry juice
1 package no sugar needed pectin
1/2 tsp stevia, or to taste (this amount made a tart jam, which I like)

Mash the thawed berries with a potato masher. Measure the 4 cups of mixed berries and 1 cup of fruit juice into a large, deep stainless steel saucepan. Whisk in No Sugar Needed Fruit Pectin until dissolved. Stirring constantly, bring fruit mixture to a boil over high heat. If using, add sweetener (sugar or SPLENDA®) and return mixture to a boil. (I added the stevia after boiling for 3 minutes, but it’s heat stable so before boiling should be fine, too.) Stirring frequently, boil 3 minutes. Remove from heat. Skim foam.

At this point, I put the jam in 4 1-cup jars. After they cooled, I put one in the fridge and 3 in the freezer. If you want to can it, use the instructions at the link above.