Heat 2 tbsp olive oil in a 10" to 12"' skillet or wok on medium high heat (nonstick and stainless steel is fine). When your pan is hot, add onions and stirfry until semi-translucent (approx 3 mins), then add chopped garlic and fry some more (approx 30 secs).
Add your red chillies, and continue frying for about 30 secs, and add the curry powder. (You may need to drizzle more oil in order to get the curry powder fully coated and sizzling.)
Turn down the heat to medium. (You want to get a nice sizzle but don't want to burn the curry). Fry the curry with enough oil and your aromatics until it is fragrant, about 2-3 minutes. It should look like this.
Once your curry paste doesn't look raw anymore, add your protein.
Fry it until it's about half done, then add the salt and fish sauce for flavor.
Continue frying until the protein is fully cooked, about 3 minutes.
Add the pineapple, and mix it well. You want to soften and simmer on medium heat gently, about 5 minutes.
Once your pineapple looks cooked, add the coconut milk. I like to keep it light by using 1/2 cup, but if you want more sauce and richness, use 1 cup.
Continue simmering for about 4 mins, or until the coconut milk is fully incorporated with the curry gravy, and it looks like a beautiful golden yellow like here. Taste your curry and season it to taste. If you like your curry on the saltier side, you can add more fish sauce or salt.
Finally, garnish your curry with cilantro. Serve the curry with piping hot rice and any steamed vegetables of your choice, or portion it out for your meal prep like what I've done here.