Jeg laver en dej med mel, vand og gær.

Lave is the normal verb for making/preparing something concrete, especially food, meals, mixtures, and similar things. So jeg laver en dej sounds natural.

Gøre usually means do, or make in more abstract expressions, such as:

• gøre rent = clean up
• gøre nogen glad = make someone happy

So jeg gør en dej would not be correct here.

Danish nouns have grammatical gender:

• en for common gender
• et for neuter

Dej is a common-gender noun, so it is en dej.

Unfortunately, there is no perfect rule that lets you guess every noun’s gender, so it is best to learn the noun together with its article:

• en dej
• et brød

A useful extra form to learn is the definite singular:

• en dej → dejen

Because the sentence treats dej as one dough / one batch of dough, so it takes the indefinite article en.

But mel, vand, and gær are being used as mass nouns or materials, just like flour, water, and yeast in English. When Danish uses them in a general ingredient sense, it normally does not add en or et.

So:

• en dej
• med mel, vand og gær

is completely natural.

Yes, but it changes the feel a little.

• Jeg laver en dej = I am making a dough / a batch of dough
• Jeg laver dej = I make dough or I am making dough in a more general sense

So in your sentence, en dej sounds natural because you are talking about one specific dough mixture.

Med means with, and here it introduces the ingredients.

So en dej med mel, vand og gær is literally a dough with flour, water, and yeast.

In food-related Danish, med is very common when listing what something contains. You may also sometimes see af in similar contexts, but:

• med focuses on what is included
• af focuses more on what something is made from

It can mean either one, depending on context.

Danish usually does not have a separate everyday verb form exactly like the English be + -ing form. So the present tense laver can cover both:

• I make
• I am making

That means Jeg laver en dej can be understood as either I make a dough or I am making a dough, depending on the situation.

The sentence follows normal Danish main-clause word order:

• Jeg = subject
• laver = finite verb
• en dej = object
• med mel, vand og gær = prepositional phrase

So the pattern is:

Subject + Verb + Object + Extra information

A very important Danish rule is that in a main clause, the finite verb normally comes in second position. For example:

• Jeg laver en dej med mel, vand og gær.
• I dag laver jeg en dej med mel, vand og gær.

Notice that when I dag moves to the front, laver still stays in second position.

Danish often leaves out a word like some when talking about ingredients or other mass nouns, because the meaning is already clear.

So:

• med mel, vand og gær

sounds completely natural.

If you want to be more explicit, you can say:

• med noget mel, noget vand og noget gær

But that is usually heavier than necessary in a simple ingredient list.