I’ve come to realize the Course refers to miracles on three distinct levels.
1. Everything in Heaven is miraculous. All expressions of love, in reality, are miraculous. The soul is miraculous. Creation is miraculous. Everything real has a miraculous nature. You are miraculous. You are a miracle. Miraculousness is permanent, natural, and the way God’s thought system always functions. Miracles give LIFE. At this level miracles defy every ego limitation and law. Life itself is a miracle.
2. After the separation, God blessed the Sonship with a miracle. The miracle was the answer to the separation, a healing thought, designed to fully heal the separation. This produced the Holy Spirit. References to "the miracle" are referring to the Holy Spirit. He is the "mechanism of miracles" because He is the way by which miracles (on level 3) are produced. This "one miracle" contains all individual (level 3) miracles. Accepting "the miracle" is accepting the atonement.
3. Within the realm of perception, there are many seemingly individual miracles. Course references to "miracles" in plural refer to this. E.g. "Miracles make minds one in God." "Miracles unite you with your brother" etc. These miracles are holographic, in that each of them contains wholeness and maximal love. They are all reflections of the one miracle, all support each other, are all equal, and all transcend orders of difficulty. These are the "miracles" that you perform IN the world as a miracle worker. These miracles can heal the sick, raise the dead, change perception, and repair the separations between brothers. As a subset, these may also include "shifts in perception" which are not "what a miracle is", but are one of their results. "A miracle is a correction introduced into wrong-minded thinking etc". Here the aim of miracles is to heal the separation between the sonship and induce revelation.
These are all tied together by statements such as "Miracles are a universal blessing from God through me to all my brothers." Similarly, miracles extend through Christ as their source, as in "miracles express from an inner awareness of Christ and the acceptance of His atonement."
Miracles do NOT originate at the ego level. They do not originate in your attempts to correct perception. YOU do not do them without God/Christ. Miracles require the absence of fear (ie maximal love), and express FROM a state of miracle mindedness, which is equivalent to true perception. Blocks to awareness must be removed, extensively, before FULL love is allowed to express with enough wholeness to perform a miracle. "The perceptual content of miracles is WHOLENESS." They require vertical perception which is a recognition of mind over matter cause-effect, in which the world is recognized as an EFFECT only, containing no causes, and transcends all ego laws and breaks every law of this world. Miracles are supernatural.
Miracles can correct perception. They can even correct the mind of your brother. However, "the world IS perception" and so additionally, miracles can correct the world. They have power over all forms. Earth is a world of tremendous limitation. Miracles demonstrate that this world is an illusion by changing its forms to show that they are not real. Mind is stronger than the body, and every miracle demonstrates this. Miracles can literally move mountains.
You as a miracle worker become MORE miraculous as you remove blocks to love. When you are done shifting perception, miracles do not come to a stop. Instead, you perform miracles ALL THE TIME. Miraculousness is your God-given NATURE. It is completely natural to your spirit, which is omnipresent and beyond ego laws. Your soul is permanently miraculous. To extend God’s love as LIFE is miraculous. Miracles are life-giving creative acts. They supply a lack. Death is lack of life, so miracles can raise the dead.
There is no sin and nothing impossible that miracles cannot reverse and undo. Believing otherwise is believing the hierarchy of illusions, which is a belief in orders of difficulty. Miracles are all the same. They ignore difficulty. "There is nothing your holiness cannot do." You cannot be loving without being miraculous. Atonement, which includes miracle working, is the natural profession of the Children of God.