Rinse gooseberries, then top and tail (remove stem from one end and dried blossom from the other). Add to a medium pot and top with ⅓ cup water. Simmer over low heat for 10 minutes to soften.
Add chopped strawberries and sugar, then stir to combine. Simmer for another 15 minutes over low-medium heat. Mash the berries every now and then. Add lemon juice and simmer 5 more minutes. Place a few tablespoons on a chilled plate in the refrigerator for 2 minutes to see if it's set. If not, simmer a little longer.
Pour hot mixture into 2 sterilized 8-ounce mason jars leaving ¼" headspace. Wipe the jar rims with a clean paper towel, add lids and collars, then hand tighten.
Optional Canning Instructions
Add jars to a canner filled with water and make sure the water level is at least a few inches over the jars. Bring the water to a full rolling boil then process for 10 minutes. Add 5 additional minutes for every 1000'-3000' above sea level.
Notes
If you prefer a smoother texture, you can use an immersion blender to blend the jam before pouring into jam jars.
Refrigerate unsealed jars and consume within 3 months.
I wanted to accentuate the flavor of the gooseberries so I didn't add any spices. If you'd like to add some, a touch of cinnamon might be a nice addition.
It's usually advised not to double jam or jelly recipes. I don't recommend doing so with this recipe either.
If processed in a hot water bath, the sealed jars can be stored in a pantry for up to a year.