Lay the almonds out on a baking sheet in a single layer.
Bake the almonds to slightly toast. They will JUST start to darken and you will smell the almonds. Do NOT overcook or burn as it will be bitter (err on the undercooked side). This will take approximately 10-15 minutes.
Remove the almonds from the oven and let cool slightly on the baking sheet until still warm but you are able to touch them.
Set 1 cup of the almonds aside. Put the remaining 3 cups of almonds in a food processor. Add 1 1/2 teaspoons salt. Blend.
Blend, scraping down the sides occasionally, until you reach your desired consistency. Depending on the sharpness of your blade and your preference, this can take anywhere from 10-20 minutes.
When you reach your desired consistency, add the remaining 1 cup of whole almonds. Process briefly to break them up as much or little as you want to get your crunchy texture.
Season to taste with additional salt if desired.
Store in a jar or container (room temperature is fine) for up to 2 months.
Notes
It is important that the almonds are still warm when you process them so they release their oils more easily.I have not tried this in a blender, but I imagine it could work if you typically have good results with your blender making things like pesto and hummus.If your almond butter is too thick and not cooperating, you can add a little neutral oil (canola, vegetable) to help loosen it. The nut butter also loosens more when put on warm bread than when it is cold.