Sopra la pasta metto un po’ di pangrattato per darle più sapore.

Because Italian normally drops subject pronouns when they are not needed. The verb ending in metto already tells you the subject is I.

• metto = I put
• io metto = I put, but with extra emphasis or contrast

So the sentence sounds natural without io.

Both are possible.

• sopra la pasta = on top of the pasta / over the pasta
• sulla pasta = on the pasta

In this kind of cooking sentence, sopra la pasta can sound slightly more like over the top of it, as if you are sprinkling something onto it. Sulla pasta is also very natural and common.

So this is more a matter of nuance and style than a strict grammar difference.

Yes, you can, but sopra la pasta is perfectly natural and probably more straightforward here.

With sopra, Italian can use:

• sopra la pasta
• sopra alla pasta

Both are correct, but the shorter version is very common in everyday Italian.

Un po’ di is a very common expression meaning a little, a bit of, or some.

Structure:

• un po’ di + noun

Examples:

• un po’ di pane = a little bread
• un po’ di formaggio = a bit of cheese
• un po’ di pangrattato = some breadcrumbs

It is one of the most useful quantity expressions in Italian.

Because po’ is a shortened form of poco.

The apostrophe shows that part of the word has been dropped:

• poco → po’

So the correct spelling is po’, not pò.

After expressions of quantity like un po’ di, Italian normally uses di + noun with no article, when speaking in a general sense.

So:

• un po’ di pangrattato = some breadcrumbs

But if you mean a specific, already identified amount, you could use an article:

• un po’ del pangrattato che ho comprato ieri = some of the breadcrumbs I bought yesterday

In your sentence, it is just the general ingredient, so no article is needed.

Because in Italian pangrattato is usually treated as a mass noun, like an ingredient, not as separate little pieces.

So Italian says:

• il pangrattato
• del pangrattato
• un po’ di pangrattato

Even though English often uses the plural breadcrumbs, Italian normally uses the singular form for the ingredient.

Because per + infinitive often expresses purpose in Italian.

Here it means:

• per darle più sapore = to give it more flavor / in order to give it more flavor

This is a very common pattern:

• Studio per imparare = I study to learn
• Vado al supermercato per comprare il latte = I go to the supermarket to buy milk

Because Italian object pronouns attach to the end of an infinitive.

So:

• dare + le → darle

This is normal Italian grammar:

• farlo = to do it
• dirti = to tell you
• comprarlo = to buy it

So per darle is the correct form, not per dare le.

Because with dare, the receiver is an indirect object.

The structure is:

• dare qualcosa a qualcuno/qualcosa
• give something to someone/something

In the sentence:

• più sapore is the thing being given
• alla pasta is the receiver

So alla pasta becomes le, not la.

Compare:

• Do più sapore alla pasta → Le do più sapore
• not La do più sapore

That is why the sentence has darle.

Grammatically, le can mean to her, but it can also refer to a feminine singular noun.

Here it refers to la pasta, which is feminine singular. So it means:

• to it = to the pasta

English does not usually personify things this way, but Italian uses the same indirect object pronoun form for feminine nouns.

Metto is the present indicative of mettere.

In a sentence like this, the Italian present can mean different things depending on context:

• something you are doing right now
• something you usually do
• a recipe-style action being described informally

So this sentence could mean:

• I put some breadcrumbs on top of pasta... or
• When I make pasta, I put some breadcrumbs on top...

The present tense in Italian is often flexible in this way.

Sometimes, but sapore is the more natural choice here.

• sapore = flavor, taste
• gusto can also mean taste, but it can also mean preference or style

In a food sentence about making pasta taste better, dare più sapore sounds very natural.
Dare più gusto is possible in some contexts, but sapore fits better here.