This is one of our favourites and big hit with toddler:
Halibut "fish and chips"
In a bowl, combine 1/2 cup mayo, 1 tbsp.Dijon mustard, 2 tsp. lemon juice and some garlic powder if desired.
In a second bowl, mix together 100 grs crushed plain potato chips (we buy organic no salt kettle chips, they're good, but anything would work, just crush them with a pin roller until they are reduced to small crumbs) and 1 cup panko (panko is some sort of japanese bread crumbs that you can get at a japanese grocery, or substitute with coarse breadcrumbs from fresh white bread, crust removed, and let sit until dry - do not use commercial bread crumbs that are finely ground)
You will need about 4-6 halibut filets.
Dip halibut filets into the mayo mixture then dredge in the potato chip mixture, coat well.
Place coated fish in a single layer on a baking sheet and bake for 20-25 mins at 350°F, or until the crust is golden brown.