Learn Dutch: De ovenschotel heeft te weinig saus. - The casserole has too little sauce.

weinig works for both uncountable nouns (meaning "little") and countable plural nouns (meaning "few"). Here, saus is an uncountable mass noun, so te weinig saus means "too little sauce". If you used a countable plural noun, like te weinig tomaten, it would mean "too few tomatoes".

Since this lesson involves pluralization, why isn't saus pluralized here?

In this context, saus refers to the liquid substance as a whole, making it an uncountable mass noun that stays singular. You would only use the plural form sauzen if you were talking about different varieties or distinct portions of sauce (for example, "three different sauces").

What are the comparative and superlative forms of weinig if I wanted to say "less sauce"?

weinig is an irregular word. Its comparative form is minder (less/fewer) and the superlative is het minst (the least/the fewest). To say "less sauce," you would simply say minder saus.

How do we determine the definite article for compound words like ovenschotel?

In Dutch, the gender (and therefore the article) of a compound noun is always determined by its final part. Because it is de schotel (the dish), the entire compound word becomes de ovenschotel.