Frozen vegetables are a normal dinner
Peas, spinach, and mixed vegetables from the freezer are everyday foods. Cook them soft and serve a small amount.

Frozen is a real meal
Put them beside rice, potato, or another food they already accept. Frozen is not a lesser meal.
A spoon of soft peas on rice is dinner. You do not have to apologise for the bag.
Soft, and a small amount
Cook them until they squash easily for a younger toddler. A huge portion of a new vegetable is harder to face than a teaspoon.
The app can say how to serve a food for their age. Softer is the comfortable direction while chewing is still new.
Keep the yes
If they eat the rice and leave the peas, the peas stay on the plate until the meal ends. The rice did its job.
Serve the same peas again another day. One bag can be several offers.
A sentence you can say
“Peas from the freezer, and your rice.”