Wash and clean strawberries. Cut off the stems and then dice strawberries into small cubes.
Add a little over half of the diced strawberries into a saucepan with 2 tbsp of sugar (more if your strawberries aren't sweet or you want your jam sweeter).
Turn the heat onto medium and start smashing the strawberries with a fork.
Bring to a gentle boil while stirring and smashing. You still want it a bit chunky.
Let the strawberries simmer for about 1-2 minutes. Remove from heat and let cool down completely.
Once the strawberries are cooled, add a couple scoops to the bottom of your glass.
Top the strawberry jam with ice, oat milk, and then the remaining diced strawberries.