I usaully buy the premade one that's not chunky cause I use it to fill my peanutbutter and jelly cupcakes but they were all out so I tried to make my own with strawberry glaze and a few fresh strawberries anyway after blending up and adding the strawberries it's too thin, I think it might just absorb into the cupcakes, anyway I think if I add cornstarch it will ruin it, does anyone know how to get it thicker without changing the flavor?

I mix a little bit of cornstarch w/ a little granulated sugar (to keep it from clumping) and cook it until it starts to thicken. You won't ruin the flavor of your filling.

I have used instant pudding as a thickening agent before, if you have enough liquid for it to absorb you could try that, or maybe jello? not sure.

I use cornstarch as well and ir doesn't affect the taste. I add the cornstarch to the cool liquid, whisk, and boil till it thickens. Then I let it chill in the fridge. HTH

If you don't want to add more sugar, you can peel a granny smith apple and put the peels in cheesecloth and boil them in with the filling. The natural pectins in the peel will help to thicken it!