For the dough: Whisk flour, sugar, and salt. Cut in the cold vegan butter and coconut oil until the mix looks sandy. Add 4–6 Tbsp ice water + apple cider vinegar and mix just until a dough forms. Split in two, flatten into discs, and chill at least 30 minutes or overnight.
For the filling: Simmer berries, sugar, lemon juice, and cornstarch for 5–7 minutes until thick. Cool completely.
Assembly and Baking: Roll out dough, cut into circles, and place on a lined baking sheet. Add a spoonful of filling, top with another circle, seal edges with a fork, and poke a few holes. Chill 10 minutes, then bake at 375°F for 18–22 minutes until lightly golden. Cool.
For the Glaze: Whisk jam, powdered sugar, vanilla, and plant milk until smooth. Spoon or drizzle over cooled pop tarts.
