You are on the right track.
Define at least two fields in your IngredientsList table:
ID (auto-entered serial number)
Define all the other fields you need for this record
Define a field, SelectedIngredient in your original table, which I will Call MainTable.
Define two relationships between MainTable and IngredientsList. One relationship for your portal values to select from and one to display the selected record in a detail view listing all the additional fields.
MainTable::SelectedIngredient x IngredientsList::ID ( Double click the relationship line and change = to x to match all records )
MainTable::SelectedIngredient = SelectedIngredientsList::ID ( Select the box for IngredientsList and click the button with two plus signs to make a second table occurrence of IngredientsList.)
Now place a portal to IngredientsLIst on your MainTable layout. Put the Ingredients Fields you want displayed on your layout by selecting them from SelectedIngredientsList.
Your button can perform this script to display the selected Ingredient Record:
set Field [MainTable::SelectedIngredient ; IngredientsList::ID]
And you can use conditional formatting to highlight the selected row in your portal.
Note: this is for display purposes only. If you want to link a given ingredient to a given MainTable record as part of a process of building a list of ingredient records, you will need a more sophisticated implementation of this basic approach.