sanso gismu

x1 is a sauce/topping/gravy/frosting for use with x2, containing ingredient(s) including x3.

x3 is in x1, an ingredient/part/component of sauce x1. See also sanmi, mixre, stasu.

In notes:

mixre
x1 (mass) is a mixture/blend/colloid/commingling with ingredients including x2.
sanmi
x1 (mass) is a meal composed of dishes including x2.
stasu
x1 is a quantity of soup/stew/olla/olio [food] of ingredients including x2.